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  • 1970-1974  (861)
  • 1965-1969  (271)
  • Computational Chemistry and Molecular Modeling  (654)
  • Ultrastructure  (478)
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  • 101
    Electronic Resource
    Electronic Resource
    Correlation effects in the low-lying excited states of the PPP models of alternant hydrocarbons. I. Qualitative rules for the effect of limited configuration interaction (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 951-970 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Simple rules for an estimate of the correlation effects in the low-lying states of alternant hydrocarbons, as described by the Pariser-Parr-Pople Hamiltonian, are formulated. These rules are based on the alternancy and spin symmetry classification of states in both strongly and weakly correlated limits and on the valence bond characteristics of those states in the fully correlated limit. It is shown that the largest effect of the electron correlation will be found for the singlet “minus” states (using Pariser's classification of the alternancy symmetry species), a smaller effect for the triplet “plus” states, and a much smaller effect for the remaining states. These rules are exemplified by limited CI calculations including all monoexcited and all mono- and bi-excited configurations, respectively, for a number of π-electronic systems. In view of these rules the success of the PPP model in the monoexcited CI approximation may be understood.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080610
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  • 102
    Electronic Resource
    Electronic Resource
    Potential energy integrals in semiempirical MO methods (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 263-266 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The two-center core-electron attraction integral VAB in zero-differential overlap semiempirical MO methods is examined. It is concluded that core-valence orthogonality and valence symmetrical orthogonalization effects must be considered, and that these effects provide justification for the CNDO/2 approximation VAB = ZBγAB.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080213
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  • 103
    Electronic Resource
    Electronic Resource
    Static and dynamic first- and second-order properties by variational wave functions (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 293-314 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The problem of the evaluation of first- and second-order energies by the use of arbitrary variational wave functions is examined in detail for time-independent perturbations as well as for time-dependent perturbations. By using a compact formalism the general formulae to be used for the case of a fully optimized set of variational parameters are readily obtained and the most prominent features are examined. The generality of the approach is tested by showing how some widely used methods are obtained by using particular types of variational wave functions. The case of incompletely optimized sets of variational parameters is examined examined extensively and several approaches at different levels of approximation are proposed. Emphasis is put upon the importance of considering, in the calculation of higher-order energies, the variational parameters which may be of negligible importance, and thus often neglected, in the absence of perturbations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080215
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  • 104
    Electronic Resource
    Electronic Resource
    Spin projected EHF method: Calculations for a four-electron model system (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 363-372 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The spin projected extended Hartree-Fock equations for successive optimization of the orbitals are derived for the four-electron case and applied to butadiene in the PPP approximation. The method shows an excellent convergence and gives 91.4% of the correlation energy for the given model-Hamiltonian.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080305
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  • 105
    Electronic Resource
    Electronic Resource
    Molecules-in-molecules calculations with fixed resonance integrals (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 427-433 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple equation for the evaluation of resonance integrals from overlap integrals and ionization potentials of the molecular fragments is suggested for molecules-in-molecules π electron calculations. The singlet π → π* transition energies of some benzene derivatives containing donor substituents were calculated. The best results were obtained if in the expression of the resonance integral the first experimental ionization potential of the methyl derivative of the donor groups is used.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080309
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  • 106
    Electronic Resource
    Electronic Resource
    Approximate valence-shell electron unrestricted Hartree-Fock calculations with orthogonalized atomic orbitals: Proton hyperfine splittings in benzyl and related radicalsPaper presented at the First International Congress of Quantum Chemistry, Menton, France, July 4-10, 1973. (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 451-465 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A modified INDO procedure has been used to calculate the proton hyperfine splittings in benzyl and the isoelectronic anilino, phenoxy and 2-azabenzyl as well as 2- and 3-thenyl radicals. The present procedure differentiates between s-, p- and d-orbitals on an atom in estimating various integrals involving them, satisfies the rotational invariance requirements and employs an orthogonalized basis set of atomic orbitals for obtaining core-Hamiltonian matrix elements. The calculations based on using the exponents which depend only on the type of orbital and the nature of atom fail to provide correct relative order of ortho and para proton splittings in benzyl as well as anilino, phenoxy and 2-azabenzyl radicals. On the other hand, use of the exponents which are modified according to the charge densities in various orbitals leads to a high absolute value for para proton splitting compared to that for ortho proton splitting which in case of all these radicals is in agreement with experiment. A spin density calculation on benzyl, anilino and phenoxy radicals considering the variation of one-center one-electron and one-center two-electron integrals for different protons with their charges is found to yield further improvement in the relative order of ortho and para proton splittings in all these radicals. In 2- and 3-thenyl radicals the role of 3d-orbitals on sulfur has also been examined. To our knowledge, no unrestricted INDO calculations including 3d-orbitals on sulfur have been reported in the literature so far.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080311
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  • 107
    Electronic Resource
    Electronic Resource
    The loge theory as a starting point for variational calculations. I. General formalismPresented at the 7th Meeting of the International Academy of Molecular Science, July 1973. (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 499-522 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that any expectation value of any observable associated with a molecule is the sum of loge contributions and of loge pair contributions. This result provides a rigorous theoretical basis for the study of additive properties of molecules.It is demonstrated that molecular wave functions (exact or approximate) can be expressed as a sum of functions corresponding to the various electronic events. Furthermore any of these event functions can be expressed in terms of correlated loge functions. This expression suggests many kinds of variational procedures of calculating wave functions (known methods and new ones).The case in which noncorrelated completely localized loge functions are used is discussed. If continuous functions are used the variational equation reduces to a sum of independent variational equations, each one corresponding to a particular electronic event. This is not so when discontinuous functions are used or when a delocalized function is added to replace the correlation interloge function.The noncorrelated completely localized loge model is analyzed in more detail. It is seen that local spin operators can be introduced and that each event density operator is the product of the loge density operators. Therefore that model is an independent loge model. The corresponding generalized self-consistent field equations are derived. This treatment helps us to understand how a localized state of a molecule can produce an ion containing a delocalized region, a phenomenon which is sometimes at the origin of some misunderstanding in photoelectron spectroscopy. Finally it is seen how virtual loge functions can be introduced to describe excited states.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080403
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  • 108
    Electronic Resource
    Electronic Resource
    Matrix elements in configuration interaction calculations (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 605-617 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is proposed for the calculation of matrix elements among various states of atoms. A set of tensor operators is the only entity in the formalism, and all formulas involve merely the vacuum expectation values of these tensor operators and the recoupling transformation coefficients. Some numerical examples are given for the Coulomb interaction matrix elements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080410
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  • 109
    Electronic Resource
    Electronic Resource
    Hybridization by the maximum overlap methodSupported in part by the National Science Foundation (Grant GP-31373 and 14012X). (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 643-676 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A brief survey of the maximum overlap method is presented and some computational aspects of the approach are discussed. The hybrid compositions and bond overlaps are reported for some thirty small ring compounds and a list of characteristic hybrids for various structural environments is given. The table of characteristic hybrids is extended to acyclic hydrocarbons and the transferability of the maximum overlap hybrids is demonstrated. Those aspects of the method which depend on geometrical properties of molecules have been considered in some details and the discussion is extended to some structural features of cyclic systems. In particular the asymmetry of bonds of spiro carbon atom is examined and rationalization of puckering of large macrocyclic systems is presented. In the summary it is pointed to the method and its potential to discuss structural aspects of molecules at the particular level of accuracy expected to be of great use in organic and physical organic chemistry. Further development and improvement of the method is mentioned, but already in the present form it can produce hybrids which may constitute a useful basis for other more ambitious semiempirical calculations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080503
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  • 110
    Electronic Resource
    Electronic Resource
    Eigenspace manipulation in SCF theory: General formalism (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 423-426 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A general formalism in order to deal with SCF eigenspace manipulation is developed. It can be shown that the initial generalized secular equation splits into a set of secular equations, each of which in turn can modify independently any predetermined subset of the SCF manifold.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080308
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  • 111
    Electronic Resource
    Electronic Resource
    An improved Hellmann-type pseudopotential for atoms and molecules (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 435-450 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The concept of pseudopotentials offers much attractiveness for the quantum mechanical evaluation of the physical properties of atoms and molecules. The ideas of Hellmann, in which the repulsive and fermion character of inner electrons can be mimicked by an experimentally fitted, exponentially damped potential term, are especially attractive. Unfortunately, it is found that such a simple expression can only be used in a very limited number of cases, such as for the alkali metals, and even then fails for the simple case of lithium.The present study shows that the Hellmann idea can readily be extended by including a second “shielded potential” term evaluated from tabulated previous Hartree-Fock calculations. The new expression for the model pseudopotential is both simple and effective. With it, the inner potential of any of the alkali metal atoms, including lithium, can be represented so that calculation of the molecular properties of the metal dimers can be accomplished. Calculations for Li2, Na2, and K2 show the binding energies and equilibrium interatomic distances to be quite well given, in agreement with both chemical experience and spectroscopic evidence.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080310
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  • 112
    Electronic Resource
    Electronic Resource
    An investigation into the use of expansion methods in the calculation of chemical shifts and diamagnetic susceptibilities (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 745-754 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chemical shift and the diamagnetic susceptibility of the hydrogenic atom with magnetic dipole and origin of the external magnetic field vector potential noncoincident with the hydrogenic nucleus have been calculated from perturbation theory using a set of expansion functions whose radial parts are single exponent associated Laguerre functions. In contrast to hydrogenic expansion functions these functions give rapid convergence to the exact values of the second-order energy summations when centred at the hydrogenic nucleus. The rate of convergence is fairly insensitive to the choice of expansion function exponent.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080509
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  • 113
    Electronic Resource
    Electronic Resource
    Calculation of the magneto-optical activity of the hydrogen moleculeResearch supported by the National Science Foundation and the Danish Science Foundation. (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 789-797 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We calculated the Verdet constant of the hydrogen molecule. We found that the angle of rotation may be represented by φ0 = A0Hv2/(v02 - v2)2 where A0 is 3.23 × 10-33 microminutes sec2 per oersted-cm-atmosphere. This is in agreement with the experimental observations where φ0 is given by the same frequency dependence with the constant A0 × 2.72 = 10-33 in terms of the same units.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080514
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  • 114
    Electronic Resource
    Electronic Resource
    Spin-Projected extended Hartree-Fock equations. II. Odd-electron systems (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 893-899 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The spin-projected extended Hartree-Fock equations discussed in Part I for an even number of electrons are given here for the odd-electron case.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080605
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  • 115
    Electronic Resource
    Electronic Resource
    Matrix elements in all valence electron models (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 925-940 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Model Hamiltonians for all valence electron calculations are examined with regard to the possibility of obtaining consistent sets of matrix elements for the description of electromagnetic processes such as photon absorption, optical activity, and magneto-optical activity. Linear and angular momentum and position operator matrix elements are related to Hamiltonian matrix elements through symmetry relations and equations of motions. The possibility of elimination of empirical interatomic matrix elements is studied.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080608
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  • 116
    Electronic Resource
    Electronic Resource
    Symmetry in the Heitler-London method. I. The connection of the molecular point group with its electron permutation group in the Heitler-London method (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 163-169 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The connection between the electron coordinates permutation group and the molecular point group is exhibited in the framework of the Heitler-London method. It is shown that the initial wave function of a molecule in the Heitler-London method can be written in such a form, that the effect of the point group operations upon this function corresponds to the permutation of the sets of electron coordinates of the ions and the subsequent multiplication of this function by some constants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080203
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  • 117
    Electronic Resource
    Electronic Resource
    Integral transform functions and separable potentials (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 209-221 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: General forms for asymptotic wave functions are derived from properties of the relevant Green's function. The use of separable potentials constructed from the asymptotic functions is described and the relation with integral transform functions is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080208
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  • 118
    Electronic Resource
    Electronic Resource
    A comparative calculation on excited state energies of some conjugated hydrocarbons (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 247-253 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The energies of the single-configuration lowest π - π* singlet and triplet states of some conjugated hydrocarbons have been calculated by the MC-SCF method using the conjugate-gradient technique of minimisation. The results are compared with those calculated by other methods currently in use, like (a) single-configuration calculation with VN-1 potential for virtual orbitals; (b) CI calculation involving singly excited states; and (c) TDHF method. It has been concluded that the results for the MC-SCF method are very good, considering that only a single open-shell configuration is involved.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080211
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  • 119
    Electronic Resource
    Electronic Resource
    Masthead (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080301
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  • 120
    Electronic Resource
    Electronic Resource
    Validity of the three-center, four-electron model for stability of rare gas halides on the basis of exchange perturbation theory (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 335-345 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In a previous publication [1] we analyzed the stability of rare gas halides on the basis of exchange perturbation theory of the Rayleigh-Schrödinger type, using a three-center, four-electron model. In this paper, the analysis is extended to a (n + 1)-center, (n + 2)-electron model for rare gas halides of composition RXn, where R is the rare gas atom and X the halogen atom, in order to investigate the validity of the three-center, four-electron model. The compounds analyzed are XeFn, XeCln, KrFn and KrCln with n = 3 and 4, in different geometric configurations and for different states of total spin S. As before, we use exchange perturbation theory in first and second orders. The results are in good agreement with those obtained in the previous analysis and with experiments. Specifically, it is found that chlorides of rare gas atoms are not stable, that XeF4 has the square-planar configuration and that trifluorides cannot exist. The possible existence of KrF4 is discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080303
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  • 121
    Electronic Resource
    Electronic Resource
    Generalized open shell SCF theory (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 373-394 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A generalized form of the coupling operator technique in SCF theory has been developed. In the formalism presented here, the monoconfigurational problem may be treated as a particular case of the multiconfigurational framework. The matrix form of the operators has been analyzed; in the LCAO context a structure has been found which is very adequate for computational purposes.Some examples are also presented which show the usefulness of the theory, emphasising the CNDO and INDO approximations. Within the application of the method to ab initio calculations, some He and second row atoms states have been studied. The He first excited singlet is also studied, the result of the analysis of such a problem being that the nonorthogonality between the singlet functions of the fundamental and of the first excited states play a primordial role in the efficiency of the method.In no case have the calculation problems, appearing in the application of the theory, been of a more difficult nature than those normally found in the application of the formalism for closed shells.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080306
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  • 122
    Electronic Resource
    Electronic Resource
    Interaction of two H2 molecules: Comparative study of various perturbation procedures (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 467-489 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A variational calculation of the interaction between two H2 molecules using minimal basis set of 1s functions is performed to check the efficiency of various versions of the perturbation theory for intermolecular interactions. The matrix procedure starting with the zero-order Hamiltonian which is symmetric with respect to intermolecular electron permutations shows better convergence than the procedures using nonsymmetric zero approximations. This conclusion follows from the calculations of ground state and four lowest excited states for three geometric configurations of the H4 system. The behaviour of the potential curves is interpreted in terms of symmetric perturbation theory. The various contributions to the interaction energy are considered in detail. The importance of charge transfer states for the description of the intermediate range of intermolecular separations is specially emphasized.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080312
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  • 123
    Electronic Resource
    Electronic Resource
    A study of the symmetry dilemma: Second-order transitions (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 559-564 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transitions from symmetry-adapted to symmetry-broken solutions of variational problems are classified according to the nature of the discontinuity involved. Two systems in which a second-order transition occurs are studied.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080407
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  • 124
    Electronic Resource
    Electronic Resource
    Masthead (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080501
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  • 125
    Electronic Resource
    Electronic Resource
    The hammerstein integral equation: a general technique for constructing a rapidly convergent padé-type approximation to the logarithmic derivative (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 693-706 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radial one-electron Schrödinger equation can be written as a nonlinear first-order differential equation by making a suitable logarithmic transformation. The resulting Riccati equation has the equivalent Hammerstein integral representation [1], \documentclass{article}\pagestyle{empty}\begin{document}$$ \beta (r) = \int_{r' = 0}^\infty P(r') N(r,r')dr' \quad 0\buildrel{〈}\over{=} r 〈 \infty $$\end{document} where the kernel, N(r, r′) is \documentclass{article}\pagestyle{empty}\begin{document}$$ N\left( {r,\,r\prime} \right) = H\left( {r,\,r\prime} \right)\exp \left\{ {\int_{\xi = r\prime}^r {R\left( \xi \right)\beta \left( \xi \right)d\xi } } \right\} $$\end{document} and H(r, r′) is the Heaviside unit step function. This kernel is a more general one than that developed in ref. [1]. Both kernels apply in cases where the Riccati equation corresponds to a Sturm-Liouville problem.It is shown that this integral equation can be integrated by parts so that, for any local potential, the integrand decreases as the cyclic folding procedure is applied. During this cyclic folding, the kernel generates an equation that contains only coefficients of β(r)0 and β(r)1. Consequently, after truncating at the end of the nth cycle, it is possible to write down a Padé-type approximation to the logarithmic derivative as a known function of the independent variable. All coefficients in this approximation can be evaluated as simple algebraic formulations of P(r), R(r), and integrals over P(r).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080505
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    Symmetry in the Heitler-London method. II. The determination of the allowed molecular multiplets (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 171-177 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the framework of the Heitler-London method, a method for determining the allowed molecular multiplets is proposed. The method is based on the connection of the total molecular spin with the permutation symmetry of the coordinate wave function and on the isomorphism of the molecular point group with a certain subgroup of the electron permutation group. The method does not depend on the approximation in which the molecular ions are considered.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080204
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  • 127
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    Dual-basis orthonormality-constrained variation method (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 765-775 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The method of orthonormality-constrained variation is extended using a dual-basis set instead of a single orthonormal basis. The complete and the partial variation methods are discussed and applied to electronic systems. It is found that the present formulation leads to the most general equation in the coupling operator method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080511
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  • 128
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    Method of complex molecular orbitals (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 799-816 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the spirit of Löwdin's extended HF scheme, an SCF method for the description of the molecular ground state, based on complex molecular orbitals, is developed. As a special case the method of parity mixing in orbitals is formulated. A calculational procedure for solving derived secular equations is described and numerical results, obtained in the minimal basis set, are reported for the N2 and CO molecule. Resulting ground state energies are close to the energies of the CI calculations with the same set of orbitals.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080515
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  • 129
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    Electronic correlation studies. II. Self-correlated field method. Application to ground state and first 1P, 3P excited states of two-electron atomic systemsAbstracted from part of a thesis submitted by R. Lissillour to the University of Rennes, 1973. (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 825-838 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An antisymmetric pair function can be built upon two kinds of monoelectronic functions, the former ones being correlated local functions and the second ones nonlocal functions taking external effects into account. This function, brought into the generalised product function procedure by means of the density matrix formulation, makes possible the study of correlation within N-electronic systems. The results of a first application of this method to the fundamental and to 1P and 3P excited states of two-electron systems are given.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560080602
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  • 130
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    Configuration interaction calculations on the nitrogen molecule (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 61-72 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A contracted Gaussian basis set capable of describing about 63% of the correlation energy of N2 has been used in a detailed configuration-interaction calculation. Second-order perturbation theory overestimated the correlation energy by 23-50% depending on how H0 was chosen. Pair-pair interaction affects the correlation energy by about 20% while quadruple excitations have an 8% effect.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080106
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  • 131
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    Matrix elements for spin-adapted configurations (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 83-89 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that the turn-over rule which is used to simplify matrix elements between spin-projected Slater determinants may also be used to simplify formation of matrix elements between any orthonormal set of spin-coupled Slater determinants. The coefficients for the spin-coupling may then be chosen freely to reduce the number of important configurations in the secular equation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080109
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  • 132
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    Application of the distinguishable electron method (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 137-150 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to make a better assessment of the distinguishable electron method developed by Kirtman and co-workers, we have applied the method to some two-electron atoms and to H2 and LiH. Our results lend support to the contention held by Kirtman and co-workers that the distinguishable electron method is a practical way of calculating reasonably accurate physical properties.
    Additional Material: 10 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080114
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  • 133
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    Waller-Hartree spin-free method (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 523-537 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper we show that with the equivalent transformation Pr = (-1)P(Pσ)-1 the spin function dependent methods such as Slater's method without group theory or Goddard's method with group theory differ only in different antisymmetric requirements from the present Waller-Hartree spin function free method. There exists a one-to-one correspondence between Slater's determinantal wave function and the Waller-Hartree double determinantal wave function. Explicit expressions for the S2 operator, Löwdin's spin projector, matric basis and several different forms of spin-projected functions are given for the Waller-Hartree formalism. The results are compared with other methods including those of Slater, Matsen, Gallup, Goddard and Segal. The differences are quite significant. New spin operators are worked out using creation-destruction operators. A knowledge of group theory is not required in this Waller-Hartree method. We have also shown that the Waller-Hartree method is more convenient than Slater's method with spin functions especially in the evaluation of the functional HΨ/Ψ. The advantages and disadvantages in the use of a linear combination of N! Hartree products and linear combinations of all possible double determinants are discussed. In addition, a formula for the calculation of the Sanibel coefficients C(S, M, i) is obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080404
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    Nonbonded interactions in membrane active cyclic biopolymers. I. Valinomycin-potassium ion complexThe results of this paper were presented in summarized form at the Edward U. Condon International Symposium on Atomic, Molecular and Solid State Theory and Quantum Biology at Sanibel Island, Florida, U.S.A., January 1973. (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 565-583 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method for quantitative comparison of various conformers of cyclic macromolecules in terms of nonbonded interaction energy terms is proposed. The first step in the procedure is an analytical evaluation of a set of Cartesian atomic coordinates consistent with the ring closure condition and prescribed values for internal parameters. A variant of the same technique enables different conformations of the macromolecule to be generated. Nonbonded interactions of the electrostatic, polarization and dispersion type and van der Waals repulsion are calculated using the generated coordinates, empirical bond polarizability data and results of simple molecular orbital calculations. An application of the proposed techniques to the closed symmetric conformation of valinomycin indicates that the macromolecule by itself is somewhat constrained in this state but that its affinity for a potassium ion is very strong - much stronger than the hydration energy of the latter.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080408
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  • 135
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    Intermediate problems for eigenvalues (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 623-625 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080412
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  • 136
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    Ab initio calculations on urea (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 857-892 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multiconfiguration wave functions constructed from contracted Gaussian-lobe functions have been found for the ground and valence-excited states of urea. ICSCF molecular orbitals of the excited states were used as the parent configurations for the CI calculations except for the 1A1(π → π*) state. The 1A1(π → π*) state used as its parent configuration an orthogonal linear combination of natural orbitals obtained from the second root of a three-configuration SCF calculation. The lowest excited states are predicted to be the n π → π* and π → π* triplet states. The lowest singlet state is predicted to be the n π → π* state with an energy in good agreement with the one known UV band at 7.2 eV. The π → π* singlet state is predicted to be about 1.9 eV higher, contrary to several previous assignments which assumed the lowest band was a π → π* amide resonance band. The predicted ionization energy of 9.0 eV makes this and higher states autoionizing.
    Additional Material: 25 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080604
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  • 137
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    Spin-orbit interaction in polyatomic molecules: Ab initio computations with Gaussian orbitals (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 941-950 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Standard sets of Gaussian atomic orbitals (STO-3G, STO-4.31G) are used to evaluate spin-orbit coupling constants in linear molecules (CO2+, NNN) and spin-orbit effects on singlet-triplet transition intensities in formaldehyde. All spin-other orbit effects have been included. In all cases spin-other orbit interactions form a large fraction of the matrix elements. Simple formulae to evaluate spin-orbit one- and two-electron integrals over atomic orbitals are presented. Standard molecular integral programs can be used for the computation of spin-orbit integrals.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080609
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  • 138
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    Error analysis of variationally optimized upper- and lower-bound wave functions for H2+Work supported in part by the National Research Council of Canada. (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 971-980 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Wave functions which are a linear combination of H2+-type elliptical orbitals are optimized to provide either an upper bound or a lower bound to the H2+ ground state. For the latter, Temple's formula is used. Three criteria are considered to determine the relative accuracy of these wave functions: (i) energy (calculated versus exact eigenvalue); (ii) average error; and (iii) local energy. Although the lower-bound optimized wave functions obtained are the most accurate available for H2+ from approximate wave functions, they are still inferior to the corresponding upper-bound wave functions by criteria (i) and (ii). In particular, using criterion (ii), it is shown numerically that the upper-bound functions are “correct to second order,” while the lower-bound functions are almost, but not quite, “correct to second order.” Despite this, the local energy analysis, criterion (iii), reveals that the lower-bound wave functions can be more accurate than the upper-bound functions in some regions of space, and hence give more accurate values for physical properties sensitive to these regions. Examples considered are the dipole-dipole and Fermi contact interactions.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560080611
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  • 139
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    Variation of the polarizability of the hydrogen molecule ion and the hydrogen molecule with internuclear separation (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 91-95 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The variation of the polarizability of H2+ and H2 with internuclear separation R = 1.6 - R = 2.4 a.u. for H2+ and R = 1.0 - R = 2.0 a.u. for H2 is determined using a variational method suggested by Das and Bersohn. From these data, values of 〈α〉0,J for which nuclear motion due to zero point vibration and centrifugal stretching is taken into account, are calculated at 300°K. The relative percent increases of the motion averaged values compared to the equilibrium values are as follows: 10.50% for H2+ and 6.52% for H2.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080110
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  • 140
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    Floating one-center perturbation treatments for H2+-like molecules based on screened hydrogen atom or molecular puff unperturbed problems (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 119-136 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Various floating one-center perturbation schemes are developed for H2+-like molecules. Previous work for the ‘1s’ hydrogen atom approach is extended through third order in the energy. In the molecular puff approach an exact ‘closed form’ solution is obtained for the zeroth-order problem, which corresponds to a double layer molecular puff. Semianalytical results for the first-order correction to the floating molecular puff wave function and for the energy through third order are developed which offer a convenient alternative to previous approaches. Explicit calculations for ground state H2+ show that for R 〉 3aO the ‘1s’ and the more complicated ‘puff’ treatments are equivalent and that neither the ‘1s’nor the molecular puff function is an adequate zeroth-order wave function for the important intermediate values of R. The usefulness of some of these methods in a variety of problems, where one-center zeroth-order wave functions do appear to be adequate, is discussed briefly.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080113
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  • 141
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    Accurate analytical self-consistent field wave functions for Tm2+ and Tm3+ (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 73-78 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The analytical expansion self-consistent field method was employed to perform ab initio calculations for the ground states of the rare-earth ions, Tm2+, 4f13, 2F, and Tm3+, 4f12, 3H, (Z = 69). In each case the total number of basis functions used in the analytical expansions was 29, distributed as follows: 10, 8, 5, and 6, for the symmetries s, p, d, and f, respectively. All of the orbital exponents of the basis functions were optimized repeatedly, to the extent of the single-precision computer representation. Values of 〈rn〉 for the 4f orbital of both ions are also presented, for the convenience of experimentalists.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080107
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  • 142
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    Coupled Hartree Fock calculation of static dipole polarizabilities and shielding factors of open shell systems (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 97-105 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Static dipole polarizabilities and shielding factors for the 2p open shell atomic systems are presented using coupled Hartree Fock theory in the framework of the Roothaan formalism. Calculations have been performed for the ground as well as for some valence excited states. A variational approach has been adopted for the determination of the first-order perturbed functions. The results are compared with those obtained from the correlated calculations and other techniques. The shielding factor values are in excellent agreement with the theoretical N/Z ratio.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080111
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  • 143
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    Extended Hartree-Fock self-consistent field with some results for berylliumlike atomic systems (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 839-855 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The general methods of deriving the extended Hartree-Fock equations are described. The rules for going over from the energy expression in the ordinary method of calculation to that in an extended one are reformulated and illustrated. The extended Hartree - Fock equations for berylliumlike atomic systems based on the use of nonorthogonal radial orbitals are given and solved. The numerical values of overlap integrals and total energies are given and discussed.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080603
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  • 144
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    Dynamic polarizability of helium: A random phase approximation calculation (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 901-913 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The random phase approximation (RPA) or time-dependent Hartree-Fock approximation (TDHF) is reconsidered for the calculation of the dynamic polarizability for atoms. An integral equation which admits a simple numerical treatment is established. The asymptotic approximation for the electron propagator is tested for its applicability by means of comparisons with earlier results.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080606
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    Book Reviews (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 995-995 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080613
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  • 146
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    Molecular integrals over generalized gaussian basis sets (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 179-191 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is given for obtaining the common molecular integrals over generalized gaussian functions: \documentclass{article}\pagestyle{empty}\begin{document}$$ \chi_i = x^{\lambda_i}_i \exp \big\{ - \big(\alpha_i x^2_i + \alpha^{\prime}_i x^{\prime 2}_i + \alpha^{\prime\prime}_i x^{\prime\prime 2}_i\big)\big\} $$\end{document}The present algorithms are expected to be more efficient than those given in earlier work by the same author.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080205
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    On the need of precision in the calculation of the LCAO density matrix of polymers (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 201-208 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper, we point out how the precision of the LCAO density matrix elements of polymers may affect the computed properties. We propose to use a more adapted approach in order to evaluate these quantities.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080207
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  • 148
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    The Coulomb hole in the 23S state of the helium isoelectronic sequence (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 255-261 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pair distribution functions evaluated for the 23S state of the helium isoelectronic sequence from the Hart and Herzberg correlated wave functions and those corresponding to the Hartree-Fock approximation are used to determine the shape of the corresponding Coulomb holes. As a consequence of a discontinuity in the Hartree-Fock solution between He and Li+, the Coulomb hole has a different shape for He than for Li+ and the other isoelectronic ions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080212
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  • 149
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    Oscillator and hydrogenic matrix elements by operator algebra (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 585-604 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Occupation number representation of the two-dimensional harmonic oscillator and some operator formulae are used in a simple algebraic derivation of complicated integrals. The calculation of full oscillator- and radial integrals of r̂w and exp (\documentclass{article}\pagestyle{empty}\begin{document}$ (iw\hat{\varphi})$\end{document}), where w is an arbitrary positive or negative integer, are performed by an integral transform, leading to a generalized Gauss matrix element. Thus it is possible, because of the back transformation, to derive from one generalized Gauss matrix element all matrix elements which are permitted by the selection rules. Some integrals of r̂w and exp (\documentclass{article}\pagestyle{empty}\begin{document}$ (iw\hat{\varphi})$\end{document}), Laguerre polynomials, and Bessel functions are completely new. For the already known integrals, the mathematical labour is considerably reduced. The relation between the two-dimensional oscillator and the hydrogen atom and their angular momentum properties are discussed. A survey on the various methods applied to the oscillator problem, from complex integration to noncompact Lie groups, and a comprehensive bibliography on this important spectroscopic field are given.
    Additional Material: 604 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080409
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  • 150
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    Electron correlation study for two-electron atoms by a simple correlated wave function (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 755-764 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The difference in the electron correlation between H- and other two-electron atoms is clarified by the introduction of the r12 term in the wave function. By using the expansion of r12, a certain modification of the usual electron correlation factor 1 + Cr12 is introduced and its effectiveness is examined. Calculations are carried out for the ground state and the three lowest excited states (23S, 23P and 21P). The peculiar electron correlation in the ground state of H- is shown by looking at the Coulomb hole for closed- and open-shelf models in comparison with those for other two-electron atoms.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080510
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  • 151
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    Virtual orbital transformation prior to configuration interaction with localized orbitals (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 777-782 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A virtual orbital transformation is proposed involving pairing of localized occupied orbitals with virtual orbitals. The virtual orbitals are transformed so that each virtual orbital is as “close” as possible to its occupied counterpart, where closeness is the inverse of the particular definition of localization. The appropriate transformation is derived for the special case of Foster-Boys localization, and an illustrative CNDO/2 calculation on HNO is presented. INDO CI results on the series N2, CO, BF indicate that use of this transformation may reduce the number of energetically significant configurations.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080512
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  • 152
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    Molecular orbitals of nitrogen at small internuclear distances (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 817-821 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080516
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  • 153
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    Masthead (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080601
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  • 154
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    Perturbative ab initio calculations of intermolecular energies. I. Method (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 1-15 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Starting from a knowledge of approximate wave functions of the isolated molecules (or atoms) A and B, a method is proposed to build up a zeroth-order ground state and excited configurations for the complex AB in which the molecular orbitals keep their local significance. The standard Rayleigh-Schrödinger perturbation in this basis provides a decomposition of the zeroth-order interaction energy as a sum of the electrostatic and repulsion energy. In the second order, it is possible to identify the classical dispersion and polarization forces (modified by a term of order S2) and two additional contributions which are linked to the exchange possibility. The intramolecular correlation component is taken into account and compared with the correlation on the isolated molecules. It is moreover suggested that since we work in a rather limited basis set, the perturbed energy of AB must be compared with the unperturbed energies of A and B calculated in a basis including the vacant orbitals on their respective partner. Finally a possibility for going beyond the second order is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080102
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  • 155
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    Matrix formulation of the generalized Hartree-Fock methods (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 45-60 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Spin-projected one-particle density and spin density matrices are presented as polynomials of suitable unprojected quantities with generalized Sasaki-Ohno coefficients. Thus an explicit form of Harriman's theorems is given. For the two-particle spatial density matrix an expansion in direct products of powers of unprojected residual electron and spin density matrices is given. For these basic matrices of the scheme the variational spin-extended equations are formulated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080105
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  • 156
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    Symmetry adaptation and the relation between the spin-free and space-spin formulations of electronic structure (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 223-233 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An information-theoretic degree of symmetry adaptation of a ket with respect to a given group is introduced. Then the general equivalence between spin-free electronic kets and antisymmetrized space-spin kets is obtained so long as our attention is restricted to spin-independent observables. It is noted that there are spin-free kets for which there exists no single antisymmetrized space-spin ket giving all the same expectation values; the converse is also noted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080209
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  • 157
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    Transformation properties of many-electron wave functions with special attention to the relation between pair-correlated DODS and configuration interaction (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 715-732 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is presented that leads to a simple derivation of the explicit relation between pair-correlated DODS schemes (e.g., the alternant molecular orbital method and the extended valence bond method) and configuration interaction.This result is based on a reduction formula for the representations of the general linear group, GL(m), carried by the N-electron function space. Generally, this paper deals with the effect of “partitioned” orbital transformations on states with “local” permutation symmetry.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080507
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  • 158
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    Ab initio calculations on porphin (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 915-924 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio SCF calculations are reported for the porphin molecule. The positions of the central protons have been optimized, and the equilibrium geometry is found to be a linear NH ⃛ HN arrangement. The NH vibrational frequencies have been computed and are compared to experimentally measured quantities. Several low ionized states have also been studied in separate spin-restricted SCF calculations. The lowest state is found to have B1u symmetry with an ionization potential of 8.0 eV.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080607
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  • 159
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    Basis dependence of wave functions of the ground state and low-lying excited states of planar formaldehydeThis is a part of a thesis for the Ph.D degree conferred by the Hokkaido University. (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 981-993 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By the use of three bases containing 3p STO's possessing different diffuseness, the electronic structure of several excited states (valence- and Rydberg-type) of planar formaldehyde is investigated by limited CI calculations. The spatial extension of the valence-type state is independent of the bases, whereas a diffuse orbital is important in describing the Rydberg-type state. The natural orbital analysis shows that the Rydberg-type states can be described as an outer electron plus an electronic cloud representing the ionized state to which the Rydberg states converge.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080612
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  • 160
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    Masthead (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080101
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  • 161
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    Perturbative ab initio calculations of intermolecular energies. III. The water dimer (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 29-43 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The interaction energy between two water molecules A and B is calculated by the method described in Paper I [1], previously applied for the interaction between two helium atoms (Paper II) [2]. This interaction energy is obtained as the difference between the energies of the complex (A + B) and the monomers (A) and (B), obtained by a perturbation method. The results obtained with the perturbation developed up to the second order in a minimal atomic basis set are decomposed into classical contributions and contributions linked to the exchange possibility. Charge transfer contributions are important and the localized character of the hydrogen bond is examined. It is pointed out that the definition of the set of excited configurations for the calculation of the energies of the isolated monomers is important, especially when one tries to use a small atomic basis set. A similar effect in SCF-type calculations is evaluated. The contribution of higher orders is evaluated by the CIPSI method.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080104
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  • 162
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    Alternative equivalent icosahedral irreducible tensors (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 153-161 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some sets of icosahedral irreducible tensors can only be defined with respect to one of two seemingly equivalent choices of axes. The problem is explained and the cases when such an alternative choice may cause mixing of sets belonging to different irreducible representations are determined. It is found that the amount of mixing is a property of the spherical basis sets and is independent of the rank and of the permutation symmetry of the tensorial sets. It is further found that certain operators which change the handedness of the coordinate axes can similarly affect these sets, notwithstanding the centrosymmetry of the icosahedron.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080202
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  • 163
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    Structure de l'ion fluoronium FH2+ et chemin de la protonation du fluorure d'hydrogeneTravail préasentéea à l'occasion du Premier congrès international de chimie quantique (4-10 juillet 1973, Menton, France) (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 193-200 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure of the ion FH2+ is investigated on the basis of semiempirical (INDO) and nonempirical (extended gaussian basis set) calculations. In agreement with experiment, both methods predict that, when going from FH to FH2+, there is a lengthening of the F—H bond; also in agreement with infrared analysis, the calculations indicate a bent structure for the fluoronium ion (valence angle at about 120°). The analysis of the FH protonation path reveals the existence of a potential barrier which is exclusively produced by solvation effects; the dependence of the proton affinity of FH on the dielectric constant of the reaction medium is also discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080206
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  • 164
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    Comments on kets not strongly symmetry adapted (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 235-245 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Various instances in which weakly or nonsymmetry-adapted kets may arise in the description of electronic systems are discussed. These cases include some types of selfconsistent field kets, exchange perturbation kets, and multistate kets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080210
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  • 165
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    Symmetries of n-electron wave functions under various spatial groups (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 267-291 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new method is used to arrive at Kotani's formula (vide infra) for the character of the representation of the group of spatial symmetry provided by functions which are eigenfunctions of the total spin operator. An alternative form involving determinants of the symmetric functions is also given. The results are applied to some cases which were untreated before and have particular interest in valence-bond calculations. The problem of the construction of bases functions of the given symmetry is also discussed, and a solution with a wide range of applicability is given.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080214
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  • 166
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    A variational perturbation treatment of the hydrogen molecular ion using the green function method on the united atom (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 319-333 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We calculated the second-order perturbed energy and the first-order perturbed wave function of the hydrogen molecular ion by the Green function method based on a united atom with effective nuclear charge, Z. Since the perturbation is given by (Z/r)  -  (1/rA)  -  (1/rB), its magnitude depends on the parameter Z. We obtain an analytical expression for the second-order perturbed energy as a function of Z and the internuclear distance R. We discuss a variety of methods to determine the best values for Z and to derive the potential energy curve and the force constant for H2+; these methods vary in the accuracy of their results.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080302
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  • 167
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    The self-consistent symmetrized OPW method with an application to crystalline selenium (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 395-422 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A review of the nonrelativistic self-consistent symmertrized orthogonalized-plane-wave (SCSOPW) method used for determining electronic energy bands in periodic solids is given. Working equations based on the full use of group theory at all stages are presented for elemental crystals. As an example the method is applied to the trigonal selenium crystal.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080307
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  • 168
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    Masthead (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080401
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  • 169
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    Brillouin-Wigner perturbation theory and the generalized eigenvalue equation (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 491-498 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Brillouin-Wigner perturbation expansion is derived for the generalized eigenvalue equation (F0 + F1)Ψ = μAΨ. The theory is applied through second order to calculate the ground-state energies of the helium atom and the hydrogen molecular ion. The results are compared with the corresponding Rayleigh-Schrödinger expansion. For the examples we consider, the Brillouin-Wigner results through second order are generally superior to the Rayleigh-Schrödinger ones.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080402
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  • 170
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    A technique for orbital exponent optimization in ab initio HF—SCF—LCAO—MO calculations (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 547-557 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A technique for Slater orbital exponent optimization in an HF—SCF—LCAO—MO calculation is proposed in which orbital exponent variation is incorporated into the SCF scheme. This is accomplished by rewriting Slater's rules so that the shielding terms depend on the molecular charge distribution through the elements of the population matrix. The SCF scheme then includes a calculation of a new set of orbital exponents from the coefficients of self-consistent molecular orbitals obtained from the previous set of exponents. The process is iterated until the energy attains its lowest value.The technique is illustrated by minimal basis calculations on LiH, BH, and HF. Near optimization is obtained with considerably less effort than is necessary for other reported techniques. Aside from interesting properties, the technique can be important for extended basis calculations where exponent optimization is a difficult task.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080406
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  • 171
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    Gradient of the general energy expression (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 619-621 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080411
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  • 172
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    Announcement (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 633-633 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080414
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  • 173
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    Simplification of Kronecker products for the representations of point groups having only one n-fold axis with n ≧ 3 (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 627-632 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080413
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  • 174
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    Hammerstein integral equivalent of Riccati's equation (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 677-692 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A transformation exists which allows the general Riccati equation \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c}{{dy\left( r \right)} \mathord{\left/ {\vphantom {{dy\left( r \right)} {dr = A\left( r \right) + }}} \right. \kern-\nulldelimiterspace} {dr = A\left( r \right) + }}B\left( r \right)y\left( r \right) + C\left( r \right)y\left( r \right)^2 \hfill & 0\leqq r 〈 b \end{array}$$\end{document} to be written in a simpler form: \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$$ d\beta (r)/dr\, = \,P(r)\, + \,R(r)\beta (r)^2 \quad 0\buildrel{〈}\over{=} r 〈 b $$\end{document} The transformed equation has the equivalent nonlinear Hammerstein integral equation \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c}\beta (r) = K\int_{r^{\prime} = 0}^b P(r^{\prime}) N(r, r^{\prime})dr^{\prime} \quad 0\buildrel{〈}\over{=} r 〈 b \end{array}$$\end{document} if the kernel N(r, r′) satisfies three conditions: \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {({\rm i})} & {\{ d/dr - R(r)\beta (r)\} N(r,r)} \\ \end{array}\, = \,\delta (r,r)/K $$\end{document} and \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {({\rm ii})} & {\{ d/dr'\, + \,R(r')\beta (r')\} N(r,r')} \\ \end{array}\, = \, - \delta (r,r')/K $$\end{document} and \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {({\rm iii})} & {{\rm [}\beta (r')N(r,r'){\rm ]}_{r' = 0}^b } \\ \end{array} = 0 $$\end{document}A solution of the nonlinear integral equation is devised by repeatedly integrating the Hammerstein equation. During this procedure the kernel generates an equation that contains only coefficients of β(r)0 and β(r)1. As a result, after truncating at the end of the nth cycle, it is a simple matter to write down a Padé-type approximation: all coefficients in this approximation are capable of being evaluated in terms of simple algebraic formulations of P(r), R(r), and integrals over P(r).The zeroes of the denominator of the Padé-type approximation define the points where singularities occur in β(r).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080504
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  • 175
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    Equivalence-restricted open-shell SCF theory (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 707-714 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is presented for generating open-shell equivalence-restricted SCF orbitals in high-symmetry situations using Roothaan-Hartree-Fock programs which are adapted for lower symmetry.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080506
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  • 176
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    Half-projected and projected Hartree-Fock calculations for singlet ground states. II. Lithium hydride (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 733-743 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The half-projected Hartree-Fock function (HPHF) for singlet states is defined as a linear combination of two Slater determinants which contains only spin eigenstates with even spin quantum numbers. The possible uses of such an approach for determining molecular properties are investigated computing the potential energy curve, binding energy, force constant, and dipole moment variation corresponding to the lithium hydride ground state. Full projected and restricted Hartree-Fock calculations (PHF and RHF) are performed simultaneously for comparison purposes. It is found that the HPHF model yields very satisfactory results, very close to those of the PHF scheme. Both models predict properly the molecular behavior as a function of nuclear separation, whereas the RHF one fails. A discussion is given in terms of configuration equivalents. It is concluded that the HPHF scheme seems to be useful for determining molecular properties specially in the case of large systems in which the more sophisticated methods are unmanageable.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080508
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  • 177
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    A general ab initio molecular multi-configuration self-consistent field algorithm (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 783-788 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ab initio multiconfiguration self-consistent-field (MC SCF) techniques and computer programs of Basch [1, 2] and the ab initio configuration interaction (CI) techniques and programs of Whitten and Hackmeyer [3] have been combined and generalized to form a general technique and program to yield optimized ab initio MC SCF wavefunctions for any set of Slater determinants. The Slater determinants are read in as input data to the program along with the spin parity that is being considered (optional) and the program successively does the CI calculation and one iteration of the SCF calculation, constructing the proper Fock-Hamiltonians by examining the set of Slater determinants and their CI coefficients. The Fock-Hamiltonian matrices are calculated and diagonalized in succession, a single two-dimensional array being used to store these matrices. The basis function integrals are read from a tape only once during each MC SCF iteration (one MC SCF iteration = a CI calculation followed by one iteration of the SCF calculation).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560080513
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  • 178
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    Licht- und elektronenmikroskopische Untersuchungen an den peritubulären Zellen des Schweinehodens während der postnatalen Entwicklung (1973)
    Springer
    Anatomy and embryology 143 (1973), S. 49-64 
    Details
    ISSN: 1432-0568
    Keywords: Testicular peritubular cells ; Boar ; Postnatal development ; Ultrastructure ; Contractility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Membrana propria der Hodentubuli des Schweines zeigt einen deutlichen Schichtenbau: Auf die Basalmembran des Tubulusepithels (a) folgen eine nicht-celluläre Lage mit Kollagenfibrillen (b), die von einer inneren (c) und einer äußeren (e) Basalmembran umhüllten peritubulären Zellen (d) und dann das intertubuläre lockere Bindegewebe (f). Die ausdifferenzierten peritubulären Zellen haben viele morphologische Merkmale mit glatten Muskelzellen gemeinsam. So besitzen sie Plasmalemmeinbuchtungen in Form pinocytotischer Bläschen sowie eine große Anzahl von Filamenten mit einem Durchmesser von 60–70 Å, welche über elektronendichte Strukturen an der Innenseite des Plasmalemms befestigt sind. Ein Golgi-Apparat, rauhes endoplasmatisches Reticulum, Mitochondrien und Mikrotubuli bevorzugen eine kernnahe Position. Im Gegensatz zu den Verhältnissen bei anderen Species sind viele charakteristische Eigenschaften der peritubulären Zellen schon vor der Pubertät ausgebildet. Die Filamente können bereits am 4. Tag als feines Netzwerk beobachtet werden, sie erfahren am 25. Tag eine starke Vermehrung und sind von nun an regelmäßig orientiert. Auch andere Befunde sprechen dafür, daß die peritubulären Zellen um den 25. Tag eine gesteigerte Aktivität entfalten. Die histochemisch nachgewiesenen Konzentrationen von alkalischer Phosphatase, Adenosintriphosphatase und Glucose-6-phosphatase erreichen zu diesem Zeitpunkt die hohen Werte, die auch für die weitere Entwicklungsphase und die ausdifferenzierten peritubulären Zellen typisch sind. Pinocytotische Bläschen erscheinen in größerer Anzahl ab dem 97. Tag. Mit dem 140. Tag sind die peritubulären Zellen morphologisch ausdiffrenziert.
    Notes: Summary The boundary tissue of the porcine testicular seminiferous tubule (membrana propria) exhibits a distinct stratification: the basement lamina of the tubular epithelium (a) is followed by a non-cellular layer with collagen fibrils (b), the peritubular cells (d) with an inner (c) and outer (e) basement lamina and finally the intertubular loose connective tissue (f). Fully developed peritubular cells have many morphological features in common with smooth muscle cells, for instance inpocketings of the plasmalemma (pinocytotic vesicles) and a great number of filaments measuring 60–70 Å in diameter. These filaments are fixed at the inner side of the plasmalemma by means of electron-dense structures. The Golgi apparatus, rough endoplasmic reticulum, mitochondria and microtubules prefer a juxtanuclear position. In contrast that is seen in other species the porcine peritubular cells develop many of their characteristic features before puberty. In samples of the 4th day a fine network of filaments is already visible within the cytoplasm. These filaments are strongly augmented at the 25th day, and from now on they are arranged in a regular fashion. Other findings, also, underline an increased activity of the peritubular cells around day 25. At that time the concentrations of histochemically demonstrated alkaline phosphatase, adenosine triphosphatase and glucose-6-phosphatase reach the high levels typical for the stages of further development and the fully differentiated cells. Pinocytotic vesicles appear in great numbers from day 97. At the 140th day the morphology of the porcine peritubular cell is completely developed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519910
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  • 179
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    The early development of the median thyroid gland of the mouse (1973)
    Springer
    Anatomy and embryology 139 (1973), S. 319-336 
    Details
    ISSN: 1432-0568
    Keywords: Fetal thyroid ; Microfilaments ; Lysosomes ; Acid phosphatase ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The mesobranchial area and the median thyroid anlage of embryonic albino mice were investigated from the somite stage 4 to 40 (81/2–10 days of gestation). In stage I (5–25 somites), there is an unequal growth and differentiation of the epithelium in the floor of the pharynx, whereby a mesobranchial area with a stratified or pseudostratified epithelium is formed. This area is distinct from the remaining pharyngeal epithelium, among other things by an apical microfilament system in the superficial epithelial cells. It is found just basal to a row of plump cytoplasmic protrusions, which extend into the lumen of the pharynx. In stage II (26–40 somites), the cranial part (median thyroid anlage) of the mesobranchial area thickens in relation to the caudal part and grows down into the underlying mesenchyme. The filament system is concentrated in the superficial cell layer of the median thyroid anlage at the beginning of stage II and disappears during downgrowth. In both stages, but most pronounced in stage II, there is a population of 0.1–5 μ intracellular bodies, which occasionally contain the remains of organelles. The larger bodies, which often contain the remains of nuclei, are usually found peripherally while the smaller ones are more evenly distributed. Acid phosphatase can often be demonstrated histochemically in small bodies, while larger bodies are usually without reaction. Cells with pycnotic nuclei and/or degenerated cytoplasmic components are regularly found. Acid phosphatase can also be demonstrated in Golgi complexes and surrounding vesicles. Basal to the epithelium, bodies are occasionally found which may possibly have been extruded from that tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519971
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  • 180
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    Uterine stromal morphology of the spayed, virgin rat when prepared with progesterone and oestrogen for implantation (1973)
    Springer
    Anatomy and embryology 141 (1973), S. 161-169 
    Details
    ISSN: 1432-0568
    Keywords: Rat ; Uterus ; Stroma ; Ultrastructure ; Sex steroids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of progesterone and oestrogen on the central uterine stroma has been examined in order to analyze what changes occur when the uterus is hormonally prepared for implantation. Both progesterone and oestrogen, when given separately, cause nucleolar enlargement and growth of the granular endoplasmic reticulum. However, after progesterone treatment the nuclei are large and spherical whereas they are spindle-shaped after oestrogen treatment. When oestrogen is administered to the progesterone-treated rat little change occurs in the stromal morphology. There is little morphological support to the view that oestrogen acts on the stroma to increase endometrial sensitivity. Further, progesterone seems to stimulate the synthesis of RNA and of cellular protein only in the stromal cell while oestrogen has a similar effect in all cell types of the uterus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519883
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  • 181
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    Ultrastructural aspects of the preattached pig embryo: Cleavage and early blastocyst stages (1973)
    Springer
    Anatomy and embryology 143 (1973), S. 95-114 
    Details
    ISSN: 1432-0568
    Keywords: Cleavage stages ; Blastocyst ; Pig ; Nucleus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural observations of morphological changes in nuclei and cytoplasm of pig embryos during cleavage and early blastocyst stages are presented. Compact nuclear bodies (nucleosphaeridies) are demonstrable in the cleavage stages, and occasionally in the inner cell mass of blastocysts. The transformation of nucleosphaeridies leading to the formation of a peripheral network are usually found at the eight-cell stage. In morula, nucleoli make their first appearance as clearly distinguishable morphological entities. A marked disorganization of nuclear envelope is observed near to the cytoplasmic annulate lamellae (CAL) indicating a possible process of transformation of the former to the latter. During premorula stages cytoplasmic organelles (Golgi complex, endoplasmic reticulum, and CAL) are predominantly concentrated around the nucleus. CAL associated with fibrillogranular material similar to the material of the nucleoplasm occur in juxtanuclear positions. In the two-cell stage, degenerating paternal mitochondria are observed. In the morula the number of spherical mitochondria fell while that of elongated mitochondria increase. The trophoblast cells of the blastocyst stage contain cytoplasmic microfilaments which are closely associated with cell organelles, particularly the desmonsomes. Structurally changed mitochondria near the yolk globules and inclusion bodies of various morphology are found. A basal lamina is discernible parallel to the trophoblast layer facing the blastocoel. The observations are discussed in relation to physiological phenomena known to occur during embryogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519913
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  • 182
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    Ultrastructure of a sacrococcygeal chordoma (1973)
    Springer
    Acta neuropathologica 25 (1973), S. 27-35 
    Details
    ISSN: 1432-0533
    Keywords: Ultrastructure ; Chordoma ; Sacrococcygeal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of a sacrococcygeal chordoma is presented. The cells vary in their size and electron density but are thought to have a common origin. The nuclei presented prominent nucleoli and intranuclear bodies. Centrioles were seen in some of the cells. The rough endoplasmic reticulum was prominent and in most cells was very distended and corresponded to the intracellular vacuoles of light microscopy. The contents of the rough endoplasmic reticulum and the abundant extracellular substance were similar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686855
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  • 183
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    Ultrastructure of herpes simplex virus infection of the nervous system of mice (1973)
    Springer
    Acta neuropathologica 26 (1973), S. 285-299 
    Details
    ISSN: 1432-0533
    Keywords: Herpes simplex Virus ; Ultrastructure ; Viral Infection ; Virus-Host Interaction ; Nervous System
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The nervous system and small intestine of mice infected with herpes simplex virus were examined by electron microscopy from the viewpoint of virus-host interaction. The host cells examined included the neuron, astrocyte, oligodendrocyte, and Schwann cell. The susceptibility of the latter was not less than that of the neuron. The endothelial cell, perineural fibrocyte and smooth muscle cell were also host cells. Replication of herpes virus in the nervous system was proven to be identical to that occurringin vitro; initial reproduction of nucleocapsids in the nucleus and subsequent maturation at the nuclear membrane with envelope formation, followed by discharge into the cytoplasmic reticular cavities and finally release from the host cell. Inconsistency in the distribution of virus particles and viral antigen was chiefly concerned with the host cell nucleus and the glial cytoplasm. Herpes virions, though few, were identified in the axons of peripheral nerves, and in the periaxonal space of myelinated fibres in the brain and the nerve ganglia. Virions were present in tiny vesicles in the perikarya or as naked particles. In the distal parts of peripheral nerve, there was marked dissociation in the amount of virions between Schwann cells and the axon. The significance of the endoneural space and the axon in the neural speread of infection is discussed briefly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688077
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  • 184
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    Electron microscopic study of the muscle changes in diabetic amyotrophy (1973)
    Springer
    Acta neuropathologica 24 (1973), S. 331-339 
    Details
    ISSN: 1432-0533
    Keywords: Diabetic Amyotrophy ; Muscle Biopsy ; Ultrastructure ; Type II Fibre Atrophy ; Partial Denervation ; Neurogenic Atrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Seven cases of diabetic amyotrophy were investigated by histochemistry and electron microscopy of biopsied muscles. Type II fibre atrophy of various grades was observed in the proximal atrophic muscles. Various changes of Z-band were observed in type II atrophic muscle fibres. In addition, mitochondrial changes, accumulation of glycogen, thickening of the capillary basement membrane and changes in the intramuscular nerves were also observed, both in the proximal and distal muscles. Some impaired motoneuron innervation of proximal muscles as well as distal muscles in a poorly controlled diabetic condition is suspected in “diabetic amyotrophy”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00685588
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  • 185
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    Electron microscopic visualization of proteoglycans and collagen in bovine costal cartilage (1973)
    Springer
    Calcified tissue international 13 (1973), S. 83-92 
    Details
    ISSN: 1432-0827
    Keywords: Proteoglycan ; Collagen ; Cartilage ; Electron Microscopy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'élimination de protéoglycans solubles de coupes de cartilage costal de boeuf, par extraction dans une solution de 4M d'hydrochlorure de guanidinium, permet de mettre en évidence des quantités abondantes de collagène dispersé et désagrégé dans la matrice. Les protéoglycanes, résistants à l'extraction, sont visibles sous forme de granules concentrés dans les régions périlacunaires. Les granulations plus importants des protéoglycanes semblent venir du chondrocyte. Dans la matrice, éloignée des chondrocytes, ces granules deviennent plus étroites. Un composant non granulaire “amorphe” masque les fibres de collagène, de telle sorte qu'elles sont difficilement visibles dans le cartilage intact.
    Abstract: Zusammenfassung Die löslichen Proteoglycane wurden mittels Extraktion in 4 M Guanidinhydrochlorid aus Rippenknorpelschnitten des Rindes entfernt. Dies erlaubte die Sichtbarmachung von großen Mengen von verstreuten und auseinandergerissenen Collagen in der Matrix. Die Protoglycane, welche sich nicht extrahieren lassen, erscheinen als kleine, in den perilacunären Regionen konzentrierte Körnchen. Die großen Proteoglycan-Körner scheinen in den Chondrocyten zu entstehen. Sobald sie sich in die Matrix, außerhalb der Chondrocyten, verlagern, werden die Körner kleiner. Ein nicht-granulärer, „amorpher” Bestandteil verhüllt die Collagenfasern, so daß diese im intakten Knorpel nicht deutlich gesehen werden können.
    Notes: Abstract Removal of the soluble proteoglycans from slices of bovine costal cartilage by extraction in 4 M guanidinium hydrochloride permitted the visualization of abundant amounts of dispersed and disaggregated collagen in the matrix. Proteoglycans which are resistant to extraction are seen as small granules which are concentrated in the perilacunar regions. Large proteoglycan granules appear to originate in the chondrocyte. As they come to occupy positions in the matrix distant from the chondrocyte, the granules become smaller. A non-granular, “amorphous” component masks the collagen fibers so that they cannot be readily seen in the intact cartilage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02015399
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  • 186
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    Ultrastructural analysis of phospholipase a induced changes in membranes of synaptic regions in rat motor cortex (1973)
    Springer
    Experimental brain research 16 (1973), S. 400-409 
    Details
    ISSN: 1432-1106
    Keywords: Ultrastructure ; Synapses ; Brain cortex ; Phospholipase A ; Membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of purified Naja nigricollis phospholipase A on slices from motor cortex from rat brain was analysed at an ultrastructural level. Samples stabilized directly with glutaraldehyde were compared with samples incubated in buffer with or without enzyme. Plasma membranes of nerve terminals, synaptic contact regions and synaptic vesicles were the main parameters studied. As judged by the electron microscopic technique the synaptic areas show a high resistance to the enzyme treatment. The intercellular space of the synaptic cleft seems unaltered. At the highest concentrations of the enzyme an increased density is noticed at the presynaptic part of the membrane. The extracellular space widens and nerve terminals and mitochondria become distended with increasing enzyme concentrations. The membranes all through the tissue appear ruptured to small pieces and at the highest enzyme concentrations used, altered in their structural organization. Quantitative analysis shows that the number of synaptic vesicles per unit surface area decreases, while ruptures of the plasma membranes of nerve terminals increase in number with increasing enzyme concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233431
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  • 187
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    The ultrastructure of the sinuatrial ring bundle and of the caudal extension of the sinus node in the right atrium of the rabbit heart (1973)
    Springer
    Cell & tissue research 138 (1973), S. 97-112 
    Details
    ISSN: 1432-0878
    Keywords: Heart ; Rabbit ; Sinuatrial node ; Sinuatrial ring bundle ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cells of the sinuatrial ring bundle are smaller than the ordinary myocardial cells; they have a regular outline and a large content of myofibrils exhibiting distinct H-bands and M-lines. Rudimentary T-tubules are found. The cells are connected by frequent nexus junctions, desmosomes and regions of interfibrillar contact, both on the well developed intercalated discs and at the periphery of the cells. The cells in the cauda of the sinus node, which extends alongside the crista terminalis together with the right branch of the sinuatrial ring bundle, are irregularly outlined and have a highly variable diameter (1–10 μm). They occur in clusters of closely packed cells. The content of myofibrils is sparse and the fibrils exhibit no M-lines and only weak H-bands. No T-tubules are found. The cells are not connected by intercalated discs and no nexus junctions are found. Both tissues contain unmyelinated nerves and nerve fibres. Varicosities with mitochondria and vesicles are found in close apposition to the muscle cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307081
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  • 188
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    The hypothalamo-hypophysial system in acipenseridae (1973)
    Springer
    Cell & tissue research 136 (1973), S. 461-477 
    Details
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Acipenseridae ; Neurosecretion ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neurohypophysis of sexually mature male and female Acipenser güldenstädti Brandt and Acipenser stellatus Pallas was studied light and electron microscopically. The recessus hypophysei lined with ependymal cells of two main types, “narrow” and “wide”, are in the center of the neurohypophysial “roots”. Processes from both cell types run radially to the basement membrane of the connective tissue layers abutting on the hypophysial intermediate lobe. Protrusions penetrating deep into the recessus hypophyseus are found in the apical parts of the “wide” cells. Pituicytes are rare in the neurohypophysis. The ultrastructure of both ependymal cell types and of the pituicytes is described. Nonmyelinated “Gomori-positive” (peptidergic) neurosecretory A1 and A2 type fibres and their terminals containing elementary neurosecretory granules (1400–1800 Å and 1000–1400 Å respectively) are the main structural elements of the neurohypophysis. Some “dark” and single myelinated neurosecretory fibres have been found. The adrenergic fibres (type B) were described earlier (Polenov et al., 1972a). The structural peculiarities of the neurohypophysis are discussed in functional and comparative-morphological terms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307364
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  • 189
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    Die Anordnung der Ommatidien in der Retina der Biene (Apis mellifica L.) (1973)
    Springer
    Cell & tissue research 139 (1973), S. 567-582 
    Details
    ISSN: 1432-0878
    Keywords: Compound Eye ; Apis mellifica ; Polarized light ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung 1. Die Ausrichtung der Rhabdome ist in der Bienenretina nicht konstant. 2. Die Anordnung der exzentrischen Zellen in der Bienenretina ist ebenfalls nicht konstant, und es läßt sich keine symmetrische Verteilung dieser Zellen nachweisen. 3. Die Morphologie der Retina wird im Hinblick auf die Orientierung der Honigbiene nach dem Polarisationsmuster des vom blauen Himmel reflektierten Lichtes diskutiert.
    Notes: Summary 1. The orientation of the rhabdoms shows no regularity within the retina of the honeybee. 2. The arrangement of the eccentric cells is also irregular within the retina of the honeybee. 3. The morphology of the retina is discussed regarding the ability of the honeybees to orient according to the pattern of the polarization of light reflected from the blue sky.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02028393
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  • 190
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    Scanning and transmission electron microscope studies on the sensory sucker papillae of the fish parasite Entobdella soleae (monogenea) (1973)
    Springer
    Cell & tissue research 137 (1973), S. 471-480 
    Details
    ISSN: 1432-0878
    Keywords: Touch receptors ; Sense organs ; Monogenean ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ventral surface of the posterior sucker of Entobdella soleae, a monogenean skin parasite of the sole Solea solea, is covered with more than 800 papillae ranging in size from 2.5–19 μm in diameter. The papillae are penetrated by nerves which double over themselves to form a stack-like array of lamellae running parallel to the surface of the haptor. No cilia or associated structures are present within these presumed sense organs and the papillae have no opening to the exterior. The much larger sucker papillae of a related species, E. hippoglossi, have been shown to have a similar ultrastructure. The possibility that the papillae may be contact receptors or strain receptors, providing proprioceptive information assisting the coordination of the attachment organ, is discussed and the papillae are compared with vertebrate touch receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307224
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  • 191
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    Ultrastructural observations on the germ line of Xenopus laevis (1973)
    Springer
    Cell & tissue research 138 (1973), S. 41-62 
    Details
    ISSN: 1432-0878
    Keywords: Germ cells ; Xenopus ; Spermatogenesis ; Chromatoid body ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of the male germ line in Xenopus laevis has been examined by electron microscopy. Findings have been compared to the parallel process in the female. Three structures unique to the germ line were found in both male and female cells: a fibrillar nuclear region free of DNA; largely proteinaceous masses of nuage material; and a chromatoid body. “Germ plasm” bodies of the egg and early embryo appear to represent a form of nuage material. The finding of a structure which can be identified as a chromatoid body in the female germ line is unique, as is its presence in sexually undifferentiated primordial germ cells. The chromatoid body in Xenopus, unlike that in mammals, does not persist in the spermatozoon. Instead, it dissociates into a series of coated vesicles during spermatogenesis. The chromosomal ultrastructure of meiotic prophase stages in Xenopus is similar in both sexes until diplotene, when male bivalents condense and enter meiotic metaphase instead of entering the extended lampbrush stage characteristic of the female. The multiple nucleoli present in gonia are lost at the onset of meiotic prophase, but no obvious mechanism for this process was observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307077
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  • 192
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    Ultrastructure of the gonadal wall of the sea cucumber, Leptosynapta clarki (echinodermata: holothuroidea) (1973)
    Springer
    Cell & tissue research 141 (1973), S. 319-330 
    Details
    ISSN: 1432-0878
    Keywords: Gonadal wall ; Holothuroidea (Leptosynapta clarki) ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The holothurian testes (as well as ovary) consists of three layers arranged concentrically around a central lumen which contains developing germ cells. The outer coelomic layer measuring 6 μ in thickness contains ciliated squamous epithelial cells, smooth muscle processes, nerve tracts, and occasional pigment cells. Interior to the outer layer is a haemal sinus measuring about 3 μ and consisting of haemal fluid composed of collagenous fibers and electron dense particles. Coelomocytes are embedded in this extracellular fluid matrix. The inner germinal layer, measuring 9 μ at the thickest regions consists of germinal cells, squamous epithelial cells, and coelomocytes. Occasional coelomocytes within the haemal sinus and germinal layer of the testicular wall contain spermatids enclosed within cytoplasmic vacuoles, suggesting phagocytosis as one of their cellular functions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307409
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  • 193
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    The granule-containing cell somata in the superior cervical ganglion of the rat, as studied by a serial sampling method for electron microscopy (1973)
    Springer
    Cell & tissue research 141 (1973), S. 331-345 
    Details
    ISSN: 1432-0878
    Keywords: Sympathetic ganglion ; Granule-containing cells ; Synapses ; Three-dimensional analysis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The surface of 4 granule-containing cells, in a cluster within the rat superior cervical ganglion, was studied by a serial sampling technique for electron microscopy. The result shows that all the 4 cells receive one, or three afferent synaptic boutons from the preganglionic fibers impinging upon their somata, and a somatic efferent synapse exists at two locations on each soma of the 2 of these cells. The postsynaptic element of the efferent synapse is observed to be represented by non-vesiculated and vesiculated segments of dendrites, soma and a possible axon collateral of the adrenergic principal neuron of the ganglion. There is a remarkably constant development of the attachment plaque between the granule-containing cells themselves, representing 1.7–2.3% of surface area for each cell. The surface area exposed to the extracellular space (covered only by a basal lamina) varies from 0.1 to 2.3% of the total perikaryal surface of the 4 cells. A tendency is noted that those cells without efferent synapses possess a more extensive area exposed to extracellular space than those forming somatic efferent synapse to the postganglionic elements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307410
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  • 194
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    Electronic Resource
    Fine structure of the developing spore of Nosema apis zander (1973)
    Springer
    Cell & tissue research 141 (1973), S. 469-478 
    Details
    ISSN: 1432-0878
    Keywords: Microsporida ; Nosema apis ; Developing spore ; Freeze-etching ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The mature spore possesses a thick spore coat and a particle-bearing spore membrane. The highly laminated polaroplast membranes are located at the anterior pole of the spore. Close to its base, the polar filament is surrounded by the polaroplast membrane. The polar filament runs spirally towards the posterior pole of the spore. A large portion of the polar filament is arranged in two layers. A similar arrangement was also observed in immature spores and in the sporoblast stage, although it was not so orderly arranged in the latter. The developing polaroplast membrane was observed in the immature spore, but not in the sporoblast. The sporoblast wall is much thinner than the spore coat, but has the same texture. Endoplasmic reticulum is the most prominent cytoplasmic organelle in the developing stages of Nosema apis. Porous nuclear envelopes are also observed in developing stages. The role of the endoplasmic reticulum in the formation of the polar filament, polaroplast and spore coat, and the function of the spore membrane, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307118
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  • 195
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    Fine structure of eyespots in tornarian larvae (Phylum: Hemichordata) (1973)
    Springer
    Cell & tissue research 142 (1973), S. 89-102 
    Details
    ISSN: 1432-0878
    Keywords: Photoreceptors ; Larva ; Hemichordate ; Ultrastructure ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The eyespots of tornariae of enteropneusts (Ptychodera flava from Hawaiian waters and an unknown species from southern California) were studied by electron microscopy. An ocellus is composed of two types of cells: sensory and supportive. The former is characterized by a bulbous cilium (with 9+2 axoneme) at its distal end, one or sometimes two arrays of microvilli from its sides below the cilium, and a basal axon. The latter features large, clear vesicles which presumably contained the reddish-orange pigment seen in the ocellus of a living larva. Five-day old tornariae of P. flava are positively phototactic. Both cilium and microvilli may function as photoreceptors. The tornarian ocellus studied is compared with eyespots of other invertebrates, and the evolutionary significance of its putative photoreceptors is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306706
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  • 196
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    Ultrastructural features of rat pituicytes in organotypic culture (1973)
    Springer
    Cell & tissue research 143 (1973), S. 107-116 
    Details
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Rat ; Pituicytes ; Organotypic culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neural lobes of adult rats have been explanted and organ-cultured for 5–10 days. While perivascular cells and neurosecretory fibers undergo a progressive degeneration, scattered pituicyte-like cells are observed mostly associated with each other in number of two or three cells for group. Cultured pituicytes are quite similar to in vivo pituicytes except for some particular features as the shape of the nucleus and the number of dense bodies. Furthermore they share with the in vivo pituicytes the phagocytic capacity which appears even increased as far as neurosecretory fibers are concerned. Finally, degenerating pituicytes and free lipid droplets are observed in the intercellular spaces: the significance of these facts is discussed and tentatively interpreted. The organotypic culture of the neural lobe seems to represent an experimental model useful to obtain a relatively pure population of pituicytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307454
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  • 197
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    Le système nerveux des cténaires (1973)
    Springer
    Cell & tissue research 143 (1973), S. 117-133 
    Details
    ISSN: 1432-0878
    Keywords: Nervous system ; Ctenophores ; Intra-mesogleal nervous system ; Synapses ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural evidence is given of the occurrence of nervous elements in the mesoglea of Ctenophores based on the presence of the typical synapses of this phylum. In Beroids, nervous fibers from the ectodermal nerve-net cross the epithelial basal membrane and run through the mesoglea; they are devoid of any ensheathing cell. These neurites build highly differentiated synapses upon the muscles and upon peculiar cells, tentatively named mesenchymal cells. In Cydippids, nerve fibers and nerve cell-bodies have been observed in the mesoglea of the tentacles. The mesogleal core of each tentacle contains mesenchymal cells and a thick strand of neurons and neurites, forming a kind of elongated ganglion. Neurites of either the axial neurones or the epithelial nerve-net neurones form numerous radial nerve strands across the tentacular muscles. Interneural, neuro-muscular and neuro-mesenchymal junctions are very frequent in the tentacle. As far as the organization of the mesoglea is concerned, the Ctenophora thus appear closer to Turbellaria than to Cnidaria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307455
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  • 198
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    Ultrastructural studies of oogenesis in some european amphibians (1973)
    Springer
    Cell & tissue research 143 (1973), S. 387-407 
    Details
    ISSN: 1432-0878
    Keywords: Oogenesis ; Urodela ; Yolk-formation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Oogenesis was studied in adult Triturus vulgaris (Urodela) with the electron microscope. The oocytes investigated ranged between 50 μm and 1600 μm in diameter. Two types of yolk platelet formation were found. Since both types involve the incorporation of high numbers of pinocytotic vesicles they are believed to be of an extraoocytic origin. On the basis of the order of their appearance they were named primary and secondary yolk. Five different types of vesicles were found, which participate in a variety of activities, such as yolk formation and the formation of the Golgi apparatus. They originate from four different sources, namely the nuclear membrane, the cytoplasm in connection with ribosome-like particles, the Golgi apparatus and the plasma membrane through pinocytosis. The results obtained were discussed especially with respect to differences found between the anura and the urodela, such as the presence or absence of cortical granules or equivalent structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307423
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  • 199
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    Electronic Resource
    Ultrastructure of the rat posterior pituitary gland and evidence of hormone release by exocytosis as revealed by freeze-fracturing (1973)
    Springer
    Cell & tissue research 143 (1973), S. 465-484 
    Details
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Membranes ; Exocytosis ; Ultrastructure ; Freeze-fracturing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Posterior pituitary glands from normal rats, and rats which had been deprived of water for varying periods, were examined by the freeze-fracture method. This technique reveals large areas of the nerve cell membrane. Images consistent with exocytosis as the mechanism of release of the neurohypophysial hormones were observed. These modifications were most numerous after the rat had been starved of water for 2 days. In normal rats, the large number of neurosecretory granules within the nerve fibres caused a bulging of the nerve cell membrane. The “bulges” disappeared 2 days after removal of drinking water. Regions of the membrane displaying “bulges” were characterised by the absence of the typical membrane-associated particles. It is postulated that the close proximity of the neurosecretory granules to the nerve cell membrane may result in rapid fusion of the neurosecretory granules on stimulation of the gland. The change in properties of the nerve cell membrane overlying the neurosecretory granules, as suggested by the loss of membrane-associated particles, may represent a change in the structure of the membrane to a form which is more favourable for fusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306766
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  • 200
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    Fine structure of the sensory pore present in the eyestalk of crustacea natantia (1973)
    Springer
    Cell & tissue research 145 (1973), S. 213-227 
    Details
    ISSN: 1432-0878
    Keywords: Sensory pore ; Crustacea ; Natantia ; Chemoreceptor ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'observation ultrastructurale du pore sensoriel de plusieurs espèces de Natantia révèle un complexe double. Un premier organe, le pore sensoriel principal, comprend une assise de cellules de soutien encadrant les parties distales de corps de cellules sensorielles. Ces cellules sensorielles portent des segments externes ciliaires qui se divisent dans une cavité sous-cuticulaire aplatie. En regard, la cuticule est amincie et comporte des micropores en forme de cratère et disposés par paires. A côté du pore sensoriel principal, un deuxième organe, le pore sensoriel latéral, est de taille plus réduite et est plus difficile à observer. Sous une invagination digitée de l'épicuticule, existe une cavité de forme complexe où s'épanouissent les segments externes ciliaires d'un faisceau de cellules sensorielles. Le pore sensoriel principal et le pore sensoriel latéral ont une ultrastructure de chémorécepteur.
    Notes: Summary Ultrastructural observation of the sensory pore of several species of Natantia reveals a twofold organ. A main sensory pore (M.S.P.) comprises a layer of supporting cells which encapsulate the terminal region of sensory cell bodies. These sensory cells include two ciliary processes dividing into a flat sub-cuticular cavity. The cuticle opposite is thin and perforated with crater-like paired micropores. Next to the main sensory pore, a second organ, the lateral sensory pore (L.S.P.), is smaller and more difficult to observe. A complex-shaped cavity underlies a contorted epicuticular invagination. Ciliary outer segments, belonging to a bundle of sensory cells, branch out in this cavity. M.S.P. and L.S.P. appear to be chemoreceptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307389
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