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  • 1985-1989
  • 1975-1979  (282)
  • 1977  (282)
  • Computational Chemistry and Molecular Modeling  (192)
  • Physical Chemistry  (90)
Source
Material
Years
  • 1985-1989
  • 1975-1979  (282)
Year
Keywords
  • 101
    Electronic Resource
    Electronic Resource
    Quantum theoretical calculations of van der Waals interactions between molecules. Anisotropic long range interactions (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 959-970 
    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: Presenting a relatively simple ab initio method to calculate full van der Waals interaction potentials between molecules, we give rules for the optimization of basis functions which permit the reliable evaluation of second order long range interactions. Closed expressions for the long range interaction energy are derived in which the orientational dependence is simplified to the utmost. Calculations show that even for molecules which have no dipole moment, such as ethylene, the strongly anisotropic electrostatic interactions are of the same magnitude as the dispersion interactions, but also that the anisotropic (“cross”) terms in the dispersion energy are about equal in size to the corresponding “quadratic” terms. Even though these anisotropic forces cancel to a large extent in the cohesion energy of the ethylene crystal, they can have important effects on some of the other crystal properties.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110608
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  • 102
    Electronic Resource
    Electronic Resource
    A survey of some theoretical studies of negative ions (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 971-978 
    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 quantum chemical methods employed by us to investigate the stabilities, charge densities, and bonding characteristics of atomic and molecular anions are briefly reviewed. The results of our work on chemically interesting species are surveyed, as are our initial results on the treatment of solvation effects in anionic systems. Finally, a simple-minded approach to the problem of finding shape resonances for electron-atom scattering processes is outlined.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110609
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  • 103
    Electronic Resource
    Electronic Resource
    Dynamic potential barrier and tunneling (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 1017-1020 
    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 tunneling transfer probability has been considered within the framework of the time dependent perturbation theory. It has been found that the probability of proton transfer may be enhanced by several orders when a dynamic potential barrier is assumed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110614
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  • 104
    Electronic Resource
    Electronic Resource
    Ab-initio and approximately rigorous calculations on small, medium, and large systems (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 1005-1015 
    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 have explored two areas of approximately rigorous calculations for computing nonempirical wave functions for heavy and/or large molecules orders of magnitude faster than with conventional ab-initio methods but with the same chemical accuracy.First, we have developed and used a series of programs (starting from our new fast sets of ab-initio Gaussian SCF and SCF-CI programs) incorporating ab-initio effective core model potentials (MOD-POT) which allow one to treat only the valence electrons explicitly, plus a charge conserving integral prescreening, which cuts down significantly on the number of integrals that have to be calculated, stored, or processed for a large molecule. We have named this latter procedure VRDDO (variable retention of diatomic differential overlap). With these MODPOT and MODPOT/VRDDO methods we have explored a variety of small, medium, and large systems ranging from electron affinities of atoms through to molecules of biological interest and large boron hydrides. The results compared to ab-initio SCF or SCF/CI calcuations are very good, usually within 0.001 to 0.002 a.u. for orbital energies and gross atomic populations (GAPS) and even better along potential energy curves.Secondly, we have explored the use of the MS-Xα method for less conventional molecules and properties than those for which it is customarily employed.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110613
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  • 105
    Electronic Resource
    Electronic Resource
    The AMO method at small internuclear distances (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 11-17 
    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 AMO function of the hydrogen molecule ψ = ψc + η ψi, where ψc is the covalent part and ψi the ionic part, is investigated for small internuclear distances R. We found η → -1 as R →,-1 as R → 0, contrary to the intuitively expected limit η → 1. However, near R = 0 an analytical expression of ψ is derived, showing that ψ reduces to the helium ground state as R → 0. We have proved that the empirical concept „covalent and ionic character“ should be replaced by the symmetry argument in the case of small R.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120103
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  • 106
    Electronic Resource
    Electronic Resource
    Molecular orbital calculations of metal ion interaction with nucleic acid bases. I. Binding of Cu(II) with adenine, guanine, uracil, and cytosine (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 505-514 
    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 reaction of the transition metal ion Cu(II) with nucleic acid bases - adenine, guanine, uracil, and cytosine - has been investigated by conformation energy calculations (CEC) and molecular orbital (MO) methods. Various binding sites, e.g., N7-C6NH2, N7-C6O, N3-N9, and N1 in purines and N3 and O8 in pyramidines, have been considered. It was found that the energy minima for different binding sites had different values. In addition to the energy minima in the nucleic acid base plane, we have observed out-of-plane energy minima, differing in energy by a few kcal/mol in most of the cases. The MO calculations were performed on the most favorable planar positions obtained. It was found that the presence of Cu(II) alters the charge distribution pattern of practically all the atoms of nucleic acid bases. Its main effect is to withdraw electrons from the negatively charged nitrogens and positively charged carbons. The oxygen charge did not alter significantly. The results are compared with the experimental electron spin resonance and x-ray diffraction studies and their biological significance is discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120309
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  • 107
    Electronic Resource
    Electronic Resource
    A relationship between the sizes and energies of localized molecular orbitals. I. A study of selected first-row hydrides (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 137-147 
    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 calculations have been performed on selected first-row hydrides with a large Gaussian basis set. Energy localized molecular orbitals (LMO'S) were computed and analysed in terms of their sizes and shapes. The total molecular electronic energy was partitioned into components which may be associated with an MO, and the relationship between the sizes and energies of such orbitals was examined. It was found that a simple energy-size relationship exists for core LMO'S but only approximately holds for bond LMO'S.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110111
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  • 108
    Electronic Resource
    Electronic Resource
    Accurate Thomas-Fermi-Dirac calculations for diatomic systems (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 163-178 
    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 Thomas-Fermi-Dirac equation for the electron density in a homonuclear diatomic system is solved numerically. The problems arising and methods of dealing with them are discussed and attention is given to the accuracy of the calculated energies. Comparisons are made to previously published work employing approximations, permitting a discussion of their utility.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110113
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  • 109
    Electronic Resource
    Electronic Resource
    Lattice dynamics with second-neighbor interactions. III. Green's matrix (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 189-211 
    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 theory of pth-order singular differential equations is adaptable to the study of the system of recurrence relations occurring in the problem of a one-dimensional chain with pth-neighbor interactions. By using Green's formula, a mapping is defined between the space Vn of eigenvectors to the dynamical matrix and the symplectic space V2p of boundary conditions for the recurrence equations. The properties of the resolvent are obtained from an analysis of the solutions of a system of inhomogeneous equations and Green's matrix is constructed for the case of standard Sturm-Liouvilletype boundary conditions. The Weyl surface is discussed and its properties used for the construction of square summable sequences which in turn can be employed in expansion formulas. The generalization of Weyl's m-function in the second-order case (p = 1) becomes for p ≥ 2 a p × p matrix M(λ), where λ is a complex parameter. The imaginary part Im {M(λ)} is related to the spectral properties and serves as basis for the discussion of different concepts of spectral density for the normal modes of lattice dynamical problems. An important practical result is the equation M = -Ψa-1Φa valid in the limit point case, generalizing the corresponding second-order formula.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110202
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  • 110
    Electronic Resource
    Electronic Resource
    Electrostatic corrections to extended Hückel theory (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 271-276 
    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 electrostatic correction to the energy of the EH method is deduced from the Hartree energy. A recent correction, due to Anderson and Hoffmann, is easily deduced as a particular case. Some calculations show how the correction can improve the description of stretching problems by EH calculations but poor results are obtained in bending and torsion problems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110207
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  • 111
    Electronic Resource
    Electronic Resource
    A basis set investigation for the oxygen 1s ionization potential in H2O (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 317-324 
    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 basis set dependency of the core ionization potential of water was investigated for atomic optimized Cartesian Gaussian basis sets. Basis set parameters optimized for oxygen yielded better IP's than basis set parameters optimized for fluorine. Not much was gained by using different parameters for the ground state and for the 1s hole state.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110212
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  • 112
    Electronic Resource
    Electronic Resource
    Announcements (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 704-704 
    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.560110415
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  • 113
    Electronic Resource
    Electronic Resource
    Calculation of molecular electric polarizabilities and dipole moments. II. The LiH molecule (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 733-741 
    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 use a variation-perturbation method to calculate the electric polarizabilities and the electric dipole moment of the LiH molecule. We obtain 4.455 for the perpendicular polarizability and 4.001 (×10-24 cm3) for the parallel polarizability. Our result for the electric dipole moment at equilibrium nuclear distance is 5.866, which is in excellent agreement with the experimental value 5.828 debye units.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110505
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  • 114
    Electronic Resource
    Electronic Resource
    Quantum science. Methods and structure. Edited by J.-L. Calais, O. Goscinski, J. Linderberg, and Y. Öhm. Plenum Press, New York, 1976. 595 pages. Price: $49.50 (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 1043-1043 
    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.560110617
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  • 115
    Electronic Resource
    Electronic Resource
    Coupled Hartree-Fock calculation of static dipole polarizations of open-shell ions (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 1-9 
    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 static dipole polarizabilities and shielding factors of 3p open-shell atomic systems from A1 to C1 are presented using coupled Hartree-Fock theory in the Roothaan scheme. The calculation was made for the ground as well as for some valence excited states of the ions. A variational approach was adopted to obtain the polarizability values and the results are compared with the existing data wherever possible. The shielding factor values are in good agreement with the theoretical N/Z ratio.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120102
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  • 116
    Electronic Resource
    Electronic Resource
    Correlation energy contributions to reaction heats (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 61-81 
    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: New, more accurate, Hartree-Fock limit energies (EHF) for ethane and ethylene are obtained from SCF total molecular energie using Ermler and Kern's procedure. These results, together with EHF values for other small closed shell molecules, are employed to calculate correlation energy (Ec) contributions to reaction heats. Cancellation to within 98% of the total Ec involved, and often to more than 99%, is found for a wide variety of chemical reactions, which strongly suggests that there are systematic regularities in the contribution to Ec from the different kinds of electron pairs in the valence shell. Assuming trictly localized pairs occupying orbitals having strongly directional character, Ec for the valence shell is evaluated in terms of Ec per lone pair, Ec per X—H bond, and Ec per X/X shared pair for Ne and for molecules containing first row atoms, where X is C, N, O, and F.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120107
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  • 117
    Electronic Resource
    Electronic Resource
    On the convergence of one centre partial wave treatments for diatomic molecules. H2+ (1sσg) and coulomb versus electron exchange intermolecular forces (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 35-59 
    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 semi-analytical solution for the nucleus and the internuclear midpoint centred partial wave equations representing the Schrödinger equation for the H2+-like molecule is discussed. Explicit proton and internuclear midpoint centred results for the interaction energy and the wave function for the 1sσg state of H2+ are obtained as a function of the internuclear distance R and the number of coupled differential equation N N ≦ 14 used to represent the Schrödinger equation for the molecule. These, together with some energy optimized floating one centre results for the interaction energy, are used to (1) discuss the convergence of the partial wave calculation as a function of R,N, and the position of the expansion centre, (2) discuss the concept of Coulomb versus electron exchange interaction energies, and (3) discuss briefly the convergence problems of analogous one centre perturbation theory treatments for the ground state H2+ molecule. The electron exchange H2+ (1sσg) molecule provides a severe test for the uefulness of partial wave methods.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120106
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  • 118
    Electronic Resource
    Electronic Resource
    Masthead (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977) 
    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.560110201
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  • 119
    Electronic Resource
    Electronic Resource
    Analytic techniques for the coupled multiconfiguration SCF perturbation theory (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 233-245 
    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: The perturbation theory based on the paired excitation multiconfiguration self-consistent field approach of Clementi and Veillard is considered. The coupled first-order perturbed orbital equations are analysed and an appropriate computational scheme for their solution is discussed. The proposed computational scheme is analogous to the technique employed for the solution of the coupled Hartree-Fock equations in the one-configuration approximation. However, because of the presence ofnondiagonal Lagrangian multipliers and the use of different one-electron operators for different orbitals, the present scheme raises some new computational problems. In this context a new technique for the solution of the unperturbed multiconfiguration self-consistent field equations is proposed. A simple illustration of the superiority of the multiconfiguration perturbation approach with respect to the ordinary coupled Hartree-Fock scheme is given. Also the validity of the variation formulation of the presented scheme and its relation to the finite-field approach are discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110204
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  • 120
    Electronic Resource
    Electronic Resource
    On the convergence properties of the Rayleigh-Schrödinger and the Hirschfelder-Silbey perturbation expansions for molecular interaction energies (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 247-257 
    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 Rayleigh-Schrödinger polarization and the Hirschfelder-Silbey (HS) perturbation theories are applied, through the 38th order, to the interaction of a ground-state hydrogen atom with a proton. The calculations were made with high precision using a large basis set of orbitals expressed in the confocal elliptic coordinates. The results obtained show that for small internuclear separations R the polarization series converges slowly in an oscillatory way to the energy of the ground 1sσg state of the H2+ molecule. At large R, however, the polarization expansion reproduces only the Coulomb part of the interaction energy effectively. When the value of the Coulomb energy is reached, the rate of convergence deteriorates drastically so that the exchange energy is not reproduced practically. The HS method converges fast when applied to both the 1sσg and the 2pσu states, the rate of convergence being roughly independent of the internuclear distance. If the finite basis set employed to solve the perturbation equations is stable under the symmetry operations, the HS expansion is shown to converge to the energy obtained by minimizing the Rayleigh-Ritz functional within the space spanned by the functions used in the perturbation theory calculations.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110205
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  • 121
    Electronic Resource
    Electronic Resource
    Geometric approximation for molecular polarizabiities (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 283-292 
    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: Molecular polarizabilities calculated with the geometric approximation are shown to be independent of the type of perturbation theory used. Agreement with finite field calculations, including anisotropies, is obtained for small molecules. A modified procedure for including sigma and pi contributions in a differentiated way is developed within the CNDO scheme. Applications to planar conjugated systems are displayed.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110209
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  • 122
    Electronic Resource
    Electronic Resource
    MS-Xα calculations of the electron affinities and ionization potentials of some heavy metals and their hydrides and fluoridesPresented at the International Symposium on Quantum Chemistry and Solid State Physics, Sanibel Island, Florida, January 1977. (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 471-484 
    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: MS-Xα calculations have been performed for the neutral species and the transition states for the positive and negative ions of the heavy metal atoms Mo, W, Re, Ir, Pt, and U and their diatomic hydrides and fluorides. Both nonspin-polarized and spin-polarized calculations were performed. The main purpose of this study was to gain insight into which negative ion species might be preferable to try to prepare for use in ion sources for tandem accelerators.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120306
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  • 123
    Electronic Resource
    Electronic Resource
    State vectors and propagators in many-electron theory. A unified approach (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 161-191 
    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 unitary group formulation of the many-electron problem is employed to give explicit representations of state vectors which are convenient for the discussion of progerties derived from propagatorcalculations. New results are obtained concerning the nature of various random-phase-like approximations and ground state representatives are generated from consistency requirements for the spectral resolution of the polarization propagator. The explicit solution admits the calculation of ground state average values for arbitrary operators and a variational upper bound to the ground state energy.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120114
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  • 124
    Electronic Resource
    Electronic Resource
    About the relationship between some necessary conditions for N-representabilityThis paper was presented at the Seminar on Reduced Density Operators held in New Brunswick, Canada, June 1977. (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 1033-1038 
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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 relationship between well known necessary conditions for N-representability of the reduced two-density matrix is investigated. It is shown that the G-condition implies two conditions of the operator endomorphism type: the C- and the B-condition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120606
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  • 125
    Electronic Resource
    Electronic Resource
    A Note on Differences Between Operator-Level and Function-Level Equations of Motion (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 227-229 
    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.560120119
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  • 126
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    Variational localized-site cluster expansions. VIII. Projection of spin symmetries (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 291-303 
    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 investigate the total spin structure of an approximate localized-site wave function for a collection of paramagnetic sites interacting so as to favor a singlet ground state. As the number of sites becomes infinite we obtain the distribution of weights of the different symmetry components of the localized site wave function; further, although only a very small fraction of such nonsymmetric wave functions is actually singlet, we find that it generally yields the same bulk property expectation values as its singlet-projected component.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120206
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  • 127
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    On the kashiwagi-sasaki generalization of the löwdin orthogonalization and the inverse vibrational problem (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 317-326 
    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: By use of the pseudo-inverse matrix technique the generalization of the Löwdin orthogonalization, given by Kashiwagi and Sasaki, is shown to be valid in a case of singular metric matrices for two basis sets of functions. The application of the same idea to the inverse vibrational problem brings about new procedures for solving this problem in an iterative way.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120208
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  • 128
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    Announcement (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 431-431 
    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.560120217
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  • 129
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    Orthonormalization, polar decomposition, and transformation to an effective hamiltonian (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 397-426 
    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: Klein has pointed out that des Cloizeaux's orthonormalization is just another formulation of Löwdin's symmetric orthonormalization. We demonstrate that des Cloizeaux's formulation is convenient for theoretical discussions and that it is intimately connected with polar decomposition--which is a generalization to operators of the fact that any complex number z can be written r exp (iθ) where r is positive and θ real. We generalize two other properties for z and find an interpretation of the Carlson-Keller theorem. Recently Lathouwers found that Löwdin's canonical orthonormalization leads to the eigenvectors of a positive operator. This operator is des Cloizeaux's. We discuss some variational theorems on this background and find the Courant-Hilbert-Löwdin “measure of linear independence” from a simple least squares consideration, closely related to Lathouwers' results.An orthonormalization due to Schweinler and Wigner (1970) is observed to be Löwdin's canonical. The Schweinler-Wigner maximum characterization is referred to a simple general theorem, which also implies a new maximum characterization.In Sections 6 and 7 we consider transformation to an effective Hamiltonian from the point of view of polar decomposition and symmetric orthonormalization. It turns out that the polar part of Bloch's transformation is des Cloizeaux's. The characterizations of this by both Klein and Jørgensen are visualized in a simple way.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120215
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  • 130
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    Nonrigid molecule effects on the energy levels of XeF6Based on a portion of the Ph.D. dissertation of S.N.D., University of Virginia, Charlottesville, 1976. (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 627-664 
    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 geometric and electronic structure of XeF6 is not yet fully understood, even though most of the means of structure determination available to the chemist have been employed in an effort to describe the molecule. We suggest that many of the experimental anomalies and theoretical difficulties arise from the possibility of rapid polytopal rearrangement in this system, and put forward in this report an analysis which accommodates the experimental data. We show that easy rearrangement produces substantial splittings in rigid-molecule energy levels, and with the aid of Longuet-Higgins group theory developed expressly for flexible molecules, compute energy-level schemes for a set of plausible rearrangement modes. By appropriate choice of parameters specifying the extent of splitting, we match the reported infrared and Raman spectra, and their temperature dependence. The puzzling “time lag” in the Raman (but not the infrared) spectrum is tentatively ascribed to selective relaxation of Raman-active vibrational modes.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110409
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  • 131
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    Potential energy curves for NiH and NiH2 (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 725-732 
    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: The potential energy curves for the NiH and linear HNiH molecules resulting from the 3d84s2 and 3d94s configuration of nickel are calculated using the unrestricted Hartree-Fock and perfect pairing generalized valence bond methods. NiH bonding in the 3d84s2 configuration is by means of an sp hybrid orbital which comes from the 4s2 shell leaving a singly occupied nonbonding orbital free to bond to another hydrogen atom. The bond to the 3d94s configuration contains primarily the 4s orbital leaving an empty orbital in the nickel 3d shell which in turn bonds very weakly with another hydrogen. These results are compared to similar studies of the hydrogen atom on Sc, Mn and Cu and some implications for hydrocarbon catalysis are considered.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110504
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  • 132
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    A study of the convergence in iterative natural orbital procedures (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 743-752 
    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 series of five different Iterative Natural Orbital (INO) procedures are tested for the ground state of water and are compared on the basis of their respective convergence properties. The choice of configuration space employed in these methods is shown to be a key factor in determining the results of such calculations. If the CI space is generated by taking all single excitations with respect to a series of dominant or reference configurations, it is concluded that the practice of varying such generating species at each iteration is highly desirable. In general the choice of the configuration space is found to be much more important than the attainment of strict NO convergence, whereby experience indicates that inclusion of all singly and doubly excited configurations (or at least a select subset thereof) relative to a series of dominant configurations provides the most efficient means of approximating the true NOS of a given system within the general INO framework.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110506
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  • 133
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    The pairwise correlated generalized valence bond model of electronic structure. II. A simple physical model for electron correlation (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 775-812 
    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: When electron pair correlations are incorporated into generalized valence bond wave functions, the necessary and sufficient wave functions for the quantitative description of chemical reactions are achieved. The resulting electron pair correlation functions are shown to be invariant; hence the generalized valence bond orbitals contain all the information in the correlated wave functions. In the case of pair correlation energies, this information is expressed through a simple function of the orbital overlaps. The resulting overlap approximation is applied to ground states, excited states, and transition states for chemical reactions. In all cases the exact energy is reproduced to within 0.5 kcal/mol (0.001 hartree). The pairwise correlated generalized valence bond method provides an opportunity to accurately predict reaction pathways for system of chemical interest.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110510
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  • 134
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    Electronic computation of first-order wave functions using green's functions (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 869-880 
    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: Green's functions and the symbol manipulative computer language LISP have been used to obtain exact, closed form, first-order functions and second-order energies for the first fourteen states of the hydrogen atom in electric and magnetic fields.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110513
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  • 135
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    On Löwdin's projection operators for angular momentum. I (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 917-929 
    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: Löwdin has presented his angular momentum projection operators in two forms, the sum form deduced from the product form. A direct proof of the sum form is presented here, together with a brief account of application of the technique to the pd configuration.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110605
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  • 136
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    Electron Correlation in Small Molecules. A. C. Hurley. Academic Press, London, England, 1976. VIII + 276 pp. Price: £10.50 (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 967-967 
    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.560120516
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  • 137
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    Announcements (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 969-969 
    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.560120518
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  • 138
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    Irreducible tensor operator methods in strong-field coupling (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 1017-1031 
    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 algebra of irreducible tensor operators is developed in the strong-field coupling case. The method is of general applicability to any symmetry group G including nonsimply reducible groups and mixed configurations. The Wigner-Eckart theorem is given for irreducible tensor operators as well as for their Kronecker and scalar products. The expressions required for the calculation of ligand field splitting, Coulomb repulsion, spin-orbit interaction, and Zeeman effect are given in detail. Applications to problems in the spectroscopy and magnetism of transition metal compounds are referred to.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120605
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  • 139
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    Announcement (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 1049-1049 
    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.560120608
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  • 140
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    A study of molecular one-electron properties in terms of localized molecular orbital components (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 133-143 
    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 number of molecular one-electron progperties have been analyzed by partitioning their electronic components over energy localized molecular orbitals (LMO). The ammonia and ethane molecules, calculated in an Approximately double zeta qualtiy basis set, were considered. The partitioning of the electronic components of certain one-electron properteies over LMO allows a quantitative rationalization of the sensitivity of certain properties to basis set effects due to the differeing degree of difficulty of accurately determining different LMO as measures of the molecular electron density.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120112
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  • 141
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    SCF scheme for excited states and analysis of the orbital relaxation effect for H2O and FNO (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 207-213 
    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 SCF scheme for excited states of closed-shell systems based on the direct minimization technique is discussed. The utility of the scheme is tested for several excited states of H2O. The contribution of various tyeps of optimization of orbitals occupied in the excited state is discussed using the example of H2 O and FNO. It was found that relaxation of doubly occupied orbitals always gives a significnat contribution to the lowering of the excited state energy in the SCF process. Unexpectedly, on the other hand, optimization of the excited orbital in many cases gave negligible results.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120116
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  • 142
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    Perturbation theory in the path-integral representation and its application to some simple quantum systems (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 233-246 
    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 path-integral formalism of nonrelativistic quantum theory the perturbation method is developed. This is based on the cumulative expansion of the partition function in powers of the difference between the classical actions of the exact and trial system. The trial system is constructed by replacing the Coulomb interactions by elastic ones, with parameters defined by Feynman's variational principle. The second order corrections to the ground-state energy of the hydrogen and helium atoms, the hydrogen molecule, and molecular ion have been evaluated. The results have been found to coincide with the actual values with an accuracy of 4-6%, whereas the corresponding error of the variational solution is of the order of 15-20%.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120202
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  • 143
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    Uniform quality gaussian basis sets for organo-silicon compounds (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 247-254 
    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: By applying the powerful direct optimization technique of conjugate gradients as adapted for the optimization of an open shell energy functional, a uniformly balanced (15s 10p) Gaussian basis set was obtained for the silicon atom. The quality of this basis set, as defined in terms of “exponent forces” or energy gradient |g|, is compatible with the quality of suitably chosen (10s 5p) carbon and (5s) hydrogen basis sets. Contractions better than double zeta were determined for all three bases of Si, C, and H. Using the primitive and contracted bases, ab initio SCF MO calculations were carried out on molecules of SiH4, CH4, and H2. Some of the computed results obtained for H2C = SiH2 are also included as an illustration for organo-silicon compounds.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120203
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  • 144
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    Electronic Resource
    Reduced first order density matrix for the Be ground state (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 343-353 
    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 reduced first order density matrix for the Be ground state is computed from an extensive configuration interaction (CI) wave function. A sequence of increasingly accurate CI wave functions Φq converging towards the exact Ψ is used to assess the quality of the results which include approximate bounds for the overlaps 〈Φq|Ψ〉, electron-nuclear coalescence cusp data, Weinhold's overlap between density matrices, virial ratios, occupation number spectra, and some expectation values. The nuclear magnetic shielding constant and the molar diamagnetic susceptibility are determined with 2.0 and 1.5% of uncertainty, respectively.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120211
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  • 145
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    Investigation of the convergence of an expansion of the screening-charge density for impurity ions in semiconductors (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 335-342 
    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 theories of the potential of an impurity ion in semiconductors, the common starting point is an expansion of the Fermi-Dirac integral F1/2 appearing in the screening-charge density. In the present paper, a formal test of the convergence of the series for F1/2 is carried out. The results show that, in the physically important limits of complete degeneracy and complete nondegeneracy, respectively, the series for F1/2 do converge. This establishes the validity of nonlinear Poisson equations for the impurity-ion potential, which can be solved approximately by making use of a variational principle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120210
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  • 146
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    Electronic structure calculation of [Fe(CN)6]-3 by the SCF-MSXα method: Study of optical transitions, X-ray photoelectron spectrum, and Mössbauer isomer shifts (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 383-396 
    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 SCF-MSXα method is used to determine the electronic structure of [Fe(CN)6]-3. Optical transition energies and valence electron ionization potentials are calculated and compared with experimental measurements. The electronic charge density at the Fe nucleus is calculated; this result and available electron densities at the Fe nucleus obtained by the same method for other Fe complexes are used to discuss the mechanisms involved in the interpretation of Mössbauer isomer shift values.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120214
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  • 147
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    Masthead (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977) 
    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.560120301
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  • 148
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    Test of an integral approximation scheme based on semiorthogonalized orbitals in LCAO SCF MO CI calculations of naphthalene (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 449-456 
    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 LCAO SCF MO CI calculations of naphthalene are carried out with a minimal basis set to test an integral approximation scheme proposed in a previous paper. When 71.3 and 53.0% of the two-electron integrals are neglected, the errors in the SCF total energy are only -0.0534 and -0.0006 a.u., respectively. In the latter case, the maximum absolute errors of the orbital energy and the gross AO population are 0.007 a.u. and 0.001, respectively. Even in the former case the errors of the excitation energies are less than 0.0004 a.u. Errors of oscillator strengths are also examined and are found to be tolerably small.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120304
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  • 149
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    Spin-Free quantum chemistry. XX. The alternancy quantum number (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 1001-1015 
    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 assignment of the alternancy quantum number to the N-electron states of neutral alternant hydrocarbons is discussed within the spin-free unitary group formulation. Alternancy is defined with respect to both molecular graphs and molecular orbital eigenvalues. The properties of the molecular orbitals of alternant hydrocarbons result from requiring the assignments in terms of atomic orbital and molecular orbital Gel'fand states to be consistent. State correlation arguments are used to remove the arbitrary phase factor present in previous treatments.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120604
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  • 150
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    A theoretical study of the vibrational structure in the \documentclass{article}\pagestyle{empty}\begin{document}$\tilde{A}^{2}A_{1} - \tilde{X}^{2}B_{1}$\end{document} transition of PH2Work done during S. P. So's leave in Oxford. (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 73-79 
    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 potential energy curves of the bending mode of PH2 in the ground 2B1 and the excited 2A1 states have been calculated using ab initio SCF-MO wave-functions. The radical is found, in agreement with experiment, to be bent in the two states. The calculated results clarify the interpretations of the anomalous behaviour of observed vibrational intervals, and offer an explanation of the ‘quasilinearity’; of the radical in the 2A1 state.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110107
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  • 151
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    A variational method for calculating dynamic polarizabilitiesResearch supported by NATO Research Grant No. 930 (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 129-135 
    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 investigate whether or not a previously proposed variation-perturbation method for calculating static polarizabilities can be used also to calculate dynamic polarizabilities. We find that the method can be used for frequencies below the first excitation frequency of the system. By amending and supplementing the procedures for solving the second-order equations we can obtain the same accuracy for dynamic polarizabilities as in the previous procedure for static polarizabilities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110110
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  • 152
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    A suggestion concerning the role of the L-region in carcinogenesis by polycyclic hydrocarbons (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 179-179 
    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.560110114
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  • 153
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    Conformational profile of nalorphine by PCILO calculationsPresented at the International Symposium on Quantum Biology and Quantum Pharmacology, Sanibel Island, Florida, January, 1975. (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 181-184 
    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.560110115
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  • 154
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    MO-LCAO-Calculations on polymethines. V. PPP-type calculations and configuration analyses of simple prototype dyes in terms of molecular subsystems (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 259-269 
    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 elucidate certain controversies in interpreting the π-electronic structure of some simple quinone and indigo dyes the Pariser-Parr-Pople SCβ,γ-wave-functions have been subjected to configuration analyses. Whereas 2,5-diamino-quinone (1) can be excellently represented by coupling of two trimethine-merocyanine chains, the analogous consideration is less appropriate with bispyrrolindigo (2). In this case the results of the configuration analyses indicate clearly the limited applicability of the Longuet/Higgins-Murrell-method.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110206
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  • 155
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    Calculation of intermolecular interactions within the PCILO framework using fixed wave-functions (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 293-300 
    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 PCILO method was used to calculate intermolecular interactions using fixed polarities. In this way our calculations are without any iteration cycle.The investigated supermolecules involve London-van der Waals type, hydrogen bonding type, and charge transfer type interactions, respectively. Both stabilization energies and equilibrium distances are in good agreement with the calculated values using optimized wavefunctions.Also the analysis of the individual contributions to the energy reflects well the mechanism of the intermolecular interactions.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110210
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  • 156
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    The role of double antisymmetrization (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 341-348 
    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: With the basic equivalent transformation Pσ = ∊(P)(Pr)-1 the dual bases of symmetric groups can be constructed. The importance of the double antisymmetrization is shown. The advantages of the use of the m basis as compared to the Wigner (matric) basis are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110214
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  • 157
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    PCILO Calculations on charge transfer complexes (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), 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: The equilibrium distances of the complex components and the stabilization energies were calculated for the molecular complexes ethylene-fluorine, ethylene-chlorine, tetracyanoethylene-benzene, tetracyanoethylene-durene, and quinone-hydroquinone using the PCILO method. The results are compared with the experimental values and the theoretical predictions of the CNDO/2 method.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110306
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  • 158
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    Environmental effects on hydrogen bonded systems: A quantum chemical study of proton relay model systems (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 473-484 
    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 an application of a reaction field theory of solvent effects has been made to study proton transfer mechanisms in hydrogen bonded systems coupled to an environment. The latter is simulated with reaction fields having variable strength and direction (defined with respect to the supermolecule's total dipole moment direction), together with superposed uniform external electric fields. Changes in proton potential curves and some other properties of a model water dimer and a water trimer are reported. The results are discussed in relation to relevant phenomena in biology and biochemistry, namely proton relay systems in enzymatic catalysis.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560110310
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  • 159
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    Second quantization for systems with a constant number of particles in the Dirac notationThe main results of this work have been presented at the International Symposium on Atomic, Molecular, and Solid-State Theory and Quantum Statistics at Sanibel Island, Florida, January 1974. (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 505-523 
    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 relation between the completeness condition for an appropriate one-particle basis set and the occupation number representation (second quantization) is shown for the time-independent case. The explicit expressions for the basic symmetric operators are derived in the Dirac bra-ket notation. The physical meaning of these operators, the algebra as well as the connections with the one-electron density matrix and with the projector on the Fermi sea in the one-electron approximation, follow directly from these expressions. The generalization for a nonorthogonal basis and the algebra for corresponding basic operators are formulated. The connection with the notion of the molecular diagrams of different kinds for the nonorthogonal atomic orbitals is shown. The Mulliken populations and the Chirgwin-Coulson bond orders are equal to the diagonal and offdiagonal elements of the molecular diagram 1, respectively. The matrix elements of the projector on the Fermi sea in the one-electron approximation in the representation of nonorthogonal atomic orbitals are elements of the molecular diagram 2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110312
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  • 160
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    Permutational symmetry of reduced density matrices (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 577-589 
    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 problems of permutational symmetry of the density matrices in reduction are studied. Some necessary and sufficient conditions for N, [λ1], [λ2]-derivability problem are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110405
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  • 161
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    Theory of lone pairs. II. A moment analysis of localized molecular orbitals in ten-electron hydrides (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 665-683 
    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 double-zeta quality molecular orbital calculations have been carried out on an extensive series of ten-electron hydrides. The Edmiston-Ruedenberg energy-localized molecular orbitals were calculated and the total molecular and localized orbital densities analyzed in terms of dipole moments, contour plots, and a simplified model for the orbital density involving analysis of the first and second moments. The simplified moment analysis model may be easily visualized in terms of threedimensional geometric objects, spheres, and ellipsoids. The model summarizes the information on the effective functional distribution inherent in the more detailed orbital contour plots in a clear and concise manner.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560110410
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  • 162
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    Announcements (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 703-703 
    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.560110414
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  • 163
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    Rotational invariance of INDO theories including d-orbitals into the basis set (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 705-713 
    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 proved that in general the INDO approximation to the full Roothaan theory does not lead to expressions which are invariant under a rotation of local atomic axes. However, when only s- and p-functions are used in the atomic basis set, the equations obtained are invariant due to the special properties of the p-functions. When d-orbitals are included into the basis set, rotational invariance is lost but can be restored if a supplementary approximation is introduced.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110502
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  • 164
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    Additivity model for calculations of UHF spin densities and charge densities in some methyl-substituted radical anions (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 753-758 
    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 additivity model as suggested by Moss et al. has been used for predicting spin densities in methyl-substituted radical anions. Linderberg's relation has been employed for evaluating the core-resonance integrals (βrs) and a heteroatom model for the methyl group has been used.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110507
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  • 165
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    Application of graphical methods of spin algebras to limited CI approaches. I. Closed shell case (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 813-848 
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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 time independent diagrammatic technique based on the mathematical methods of quantum electrodynamics (second quantization, Wick's theorem, Feynman-like diagrams) is combined with graphical techniques of spin algebras to derive general expressions for the matrix elements of spin independent one- and two-particle operators between spin symmetry adapted ground, mono- and bi-excited configurations of a closed shell system. Two coupling schemes are considered for bi-excited states and their relative merits are discussed. Finally, the results are used to derive compact expressions for the coupling coefficients of the direct configuration interaction from molecular integrals (CIMI) method.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110511
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  • 166
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    Perturbation theory within the variation methodAspects of the variation method 2. (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 881-884 
    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 of Moccia's formulas (Int. J. Quant. Chem. 8, 293 (1974)) for corrections to “not completely optimized variational parameters” are compared with those resulting from a perturbation theory analysis. It is not possible to choose the zero-order Hamiltonian (at least not in any simple way) so as to get exact agreement, but one choice does come close.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110514
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  • 167
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    P.-O. Löwdin's scientific and other activitiesThis is a shortened version of the introductory paper of the Symposium. (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 897-905 
    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.560110603
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  • 168
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    Completeness and linear independence of basis sets used in quantum chemistryThis material constitutes part of the doctoral thesis of one of the authors (B.K.). (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 943-957 
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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: Infinite sets of functions in Hilbert space are characterized by their completeness properties and the extent of linear independence. Different measures of linear independence such as orthonormality, Gram's determinant, the special measure of linear independence, and the asymptotic dimension are related to each other and with the degrees of completeness such as overcompleteness, exact completeness, and incompleteness as far as possible.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110607
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  • 169
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    Absorption line shape of two coupled oscillators decaying in two different mediums (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 979-989 
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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 linear response theory is used to study the line shape of two coupled oscillators, decaying in two different baths, when one of the oscillators is coupled to the radiation field. The baths are considered to be thermally excited. The analysis is based on the computation of the correlation functions 〈ai+ (t)ai (0)〉 and 〈ai (t)ai+(0)〉 of each oscillator, taking the coefficients associated with the operators ai+ and ai in the Heisenbemg representation as the starting point of the calculation. The line shape in different cases is also discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110610
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  • 170
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    Point-group symmetry and transition metal superconductivity: Nb—Mo—Tc alloys (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 11 (1977), S. 1035-1041 
    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: Using a factorization of the band density of states into point-group symmetries, it is shown that the variation of the fractional density of states of one type - Γ12 - correlates closely (ρ12 = 0.997) with variations in λM〈ω2〉. It is also shown that the Hopfield parameter η does not correlate with Np(0)Nd(0)/N(0), which would be true if superconductivity in d-band materials was dominated by local atomic processes. It is concluded that bonding plays an important role in superconductivity in Nb-Mo-Tc alloys.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560110616
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  • 171
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    Masthead (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977) 
    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.560120101
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  • 172
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    Formulas for evaluation of expectation values of monoelectric operators with modified gaussian functions (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 29-34 
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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: Formulas are presented for the evaluation of the expectation values of various monoelectronic operators. The integrals are based on „Hermite-Gausian“ or „Modified Gaussian Functions“ and are expressed in suitable form for a computer programming. It is pointed out that the final expresions are simpler than the analogou omes obtained from the usual Gausian functions and can be written as linear combinations of a few baic integrals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120105
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  • 173
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    Calculations of the magnetic shielding constants of heavy nuclei in polyatomic molecules (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 93-103 
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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: Coupled Hartree-Fock perturbation theory has been applied to compute the nuclear magnetic shielding tensors for 17O, 14N, and 13C in the molecules of water, ammonia, and methane with four wave functions of increasing accuracy, expanded over basis sets of Gaussian functions. The agreement with the experimental data available for ammonia and methane is very good. Quantities necessary to evaluate the shilding for an arbitrary gauge are also given. The degree of gauge-invariance of the calculated properties is nt satisfactory in the ammonia, while better results are found for water.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120109
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    Electronic-structure studies of solides. V. Rigorous Hartree-Fock treatment of metallic hydrogen using a plane-wave basisThe United States Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation hereon (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 145-160 
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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: We have performed Hartree-Fock calculations for simple cubic metallic hydrogen crystals using Bloch functions expanded in plane waves, All integrals were evaluated accurately including exchangeterms. Increasingly larger basis sets were used, and the total Hartree-Fock energy obtained with the maximum number of plane waves (27) was -0.4770 hartrees/atom. This total energy is believed to be within a few millihartress of the Hartree-Fock limit results. The deficiency of a plane-wave expansion to represent the atomic cusps, however, makes it difficult to obtain the exact Hartree-Fock limit with a plane-wave expansion. When the correlation energy (calculated in the random-phase approximation with Hartree-Fock bands and functions as zeroth order states) is added, and upper limit of -0.501 hartrees/atom is found for the total energy of this system. The Fermi surface was found to touch the Brillouin zone boundaries around the X points due to an appreciable depression of the band energies in that part of the Brillouin zone. The equilibrium lattice spacing (a = 2.705 bohrs) was slightly smaller than that obtained earlier with an atomic orbital basis.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120113
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  • 175
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    Tetrahedral Gaussian Lobe Functions (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 225-226 
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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
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120118
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  • 176
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    Handbook of atomic data. S. Fraga, I. Karwowski, and K. M. S. Sexena. Elsevier Scientific Publishing Company, Amsterdam, Oxford, New York, 1976. 551 pp. Price: $74 (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 231-231 
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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.560120120
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  • 177
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    Variational localized-site cluster expansions. VI. General theory revisited (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 255-271 
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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 general and systematic localized-site cluster expansion is described. It provides simple physically appealing and computationally feasible wave function ansätze, as well as, via extension of the cluster expansion, a unique expression for general, possibly exact, wave functions. We show that a variety of matrix element evaluation techniques are available and that they are sometimes exact though relatively simple. These techniques often proceed in terms of computational time proportional to the number of different types of sites, rather than their total number. Thus it seems we have a new and viable many-body theory, which is expected to be most accurate and most readily implementable when a physical picture with slightly perturbed localized sites is relevant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120204
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  • 178
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    Variation-iteration solution of the Hartree-Fock equations for atomic systems (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 305-315 
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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 recently proposed scheme based on the variation-iteration method is applied to the solution of the Hartree-Fock equations for atomic systems. The procedure depends on the repeated application of a Green's integral operator which involves a single numerical quadrature at each stage. The integrations are performed by means of a prescription described in a recent paper by the present authors and it is shown that the parallel philosophies of the self-consistent field and the variation-iteration approaches combine quite naturally. Representative calculations are carried out on three-and four-electron systems and the flexibility of the proposed scheme is demonstrated by considering solutions of various forms of the SCF equations.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120207
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    A non-empirical molecular orbital study of valence tautomers of C2H3N (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 355-368 
    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 valence tautomers of C2H3N have been examined by non-empirical molecular orbital calculations using two split-valence shell basis sets. All geometries were fully optimized using the 4-31G basis set and these structures were then used in 6-31G basis set calculations. The order of stability of the three possible cyclic isomers is 1-azirine 〉 cyclic carbene 〉 2-azirine. The profiles for conversion of vinylmethylene into cyclopropene, vinylnitrene into 1-arizine, and iminomethylene into 2-azirine have all been shown to have barriers.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120212
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  • 180
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    Announcement (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 432-432 
    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.560120218
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  • 181
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    Convergence properties of generalized inner projections to dynamic polarizabilities (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 443-447 
    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: Generalized inner projections to dynamic polarizabilities, αA (iω), are shown to give bounds to dispersion coefficients, CAB, which are improved as the dimensionality of the projections is increased. Error bounds in the regular half-planes of αA±(ω) are found from the maximum principle. Comparison with related approximations to polarizabilities is made.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120303
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  • 182
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    Electronic Resource
    Ab initio valence bond calculations. VII. HF, HF+, and H2F+ (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 515-525 
    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 valence bond calculations for the ground and excited states of HF and HF+ are presented. Total energies, equilibrium geometries, dissociation energies, dipole moments, and spectroscopic constants for HF and HF+ have been calculated. The photoelectron spectrum of HF has been examined and interpreted by means of the valence bond formalism. The ground state of the protonated species H2F+ has been investigated.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120310
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  • 183
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    Perturbation treatment of the Hartree-Fock equations of 1s2p3s 4Pθ state of the lithium isoelectronic sequence (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 561-568 
    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 first order Hartree-Fock equations of the 1s2p3s 4P0 state of the three-electron atomic systems have been solved exactly. These solutions are used to evaluate Hartree-Fock energy up to third order with high accuracy. The third order Hartree-Fock energies for Li to Ne7+ are compared with those derived from experiment and other theoretical calculations.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120314
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  • 184
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    Effect of semi-empirical parameters on the simple random-phase approximation calculations of conjugated hydrocarbons (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 639-654 
    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: Singlet-singlet transition energies, oscillator strengths, triplet energy levels, and the ground state correlation energy of a number of conjugated hydrocarbons have been calculated by the simple random-phase approximation (RPA) within the framework of the Pariser-Parr-Pople (PPP) model. The effect of semi-empirical parameters in such calculations has been examined in detail. A set of parameters has been deduced from these parametric studies which is found to yield results for the singlet spectra of the molecules in excellent agreement with experiment. It is, however, not possible to treat the triplet states using these same parameters, since they produce triplet instabilities in all the molecules. The triplet instability problem associated with semi-empirical RPA calculations has been discussed in detail.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120405
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  • 185
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    The MTXαR method. The determination and use of “molecular” α values in molecular multiple scattering Xα calculations (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 707-719 
    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 semiempirical approach is used to fix the α value for use in the extraatomic regions in multiple-scattering (MSXα) calculations which retain the muffin-tin treatment of the potential. Such a “molecular” α value for an atom is determined by requiring the corresponding homonuclear diatomic molecule to have its minimum at the experimentally determined equilibrium separation; hence they are called αR. Molecular αR values are determined for the ground state Li2 and F2 molecules and are tested in a calculation of the ground state LiF potential curve. We find a binding energy at the calculated equilibrium separation to be within 1% of the experimental value. The LiF curve based entirely on the ordinary atomic α values is substantially inferior. The present MTXαR approach appears to be competitive with others which are intended to improve the muffin-tin version of MSXα calculations.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120409
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  • 186
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    Electronic Resource
    Masthead (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977) 
    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.560120501
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  • 187
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    Selected valence electron SCF MO calculations on alkali metal diatomics (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 813-825 
    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 selected valence electron closed-shell MO theory of Pohl, Rein, and Appel has been modified with a view to accurately determining the potential energy curves and related spectroscopic quantities of alkali metal diatomics. Binding energies -De equilibrium internuclear distances re, vibrational force constants ke, and dipole moments μbond have been calculated by this method. For the determination of ke, however, use has been made of three different formulas. The calculated potential energy curves have been fitted to a semiempirical potential function constructed in terms of De, re, and ke and then following the Woolley and Dunham method, the harmonic force constants le, me, ne, and oe, the vibrational-rotational coupling constants αe, the vibrational anharmonicity constants wexe, and two other second order spectroscopic constants, viz., βe and γe, have been calculated with the potential function. The computed results have been compared with experiments wherever the latter are available and it has been observed that these results are in very good agreement with experiment.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120505
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  • 188
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    Exact calculations of Franck-Condon overlaps and of matrix elements of some potentials by means of the coherent state representation (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 859-873 
    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: Franck-Condon overlaps are described as the matrix elements of unitary operators related to the spatial displacement and the frequency shift. They are calculated exactly by means of the coherent state representation. Furthermore, the generalized matrix elements of xj, e-αx, and e-βx2 between two states with different equilibrium coordinates and frequency are evaluated in the same way.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120509
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  • 189
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    Introduction to the Electron Theory of Small Molecules. A. C. Hurley. Academic Press, London, England, 1976. X + 329 pp. Price: £12.00 (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 967-968 
    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.560120517
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  • 190
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    Laplace transform method in two-photon spectroscopy theory (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 971-983 
    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: This paper formulates a number of problems of the two-photon spectral theory and characterizes the analytical methods of solving them as worked out by the authors. The efficiency and wide application of the Laplace transform method is demonstrated by the most typical examples of the cross section analytical calculations of two-photon processes, dynamical polarizability, and bremsstrahlung at the scattering.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120602
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  • 191
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    Spin-free quantum chemistry. XIX. Particle-hole and pairing symmetriesPresented in part at the Second International Congress of Quantum Chemistry, New Orleans, Louisiana, April 19-24, 1976. (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 985-999 
    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: Particle-hole and pairing relationships are obtained within the framework of the unitary group formulation of the many-electron problem using the concept of particle-hole conjugation. Besides the familiar relationships for alternant hydrocarbons, relationships among various pericyclic reaction paths are obtained.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120603
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  • 192
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    A comparison of geometric methods with other methods for the characterization of density matricesThis paper was presented at the Seminar on Reduced Density Operators held in New Brunswick, Canada, June 1977. (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 12 (1977), S. 1039-1048 
    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 recently developed geometric methods for characterizing the subset of density matrices within the space of Hermitian matrices are compared with methods commonly used for the approximate characterization of reduced density matrices. The decomposition of a density matrix into components in terms of the reducing basis set is compared with decomposition in terms of representations of U(r).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560120607
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  • 193
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    The production and subsequent relaxation of vibrationally excited OH in the reaction of atomic oxygen with HBr (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 9 (1977), S. 97-109 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A fast discharge flow apparatus equipped for EPR detection of radicals has been used to investigate the reaction O + HBr → OH + Br. At 295°K, measurements showed that more than 97% of all OH produced in this reaction was formed initially in its first vibrationally excited state. Rate constants for physical deactivation of OH(v = 1) by O(3P), Br(2P3/2), H2O, and HBr were measured as (1.45 ± 0.25) × 10-10, (6.4 ± 2.4) × 10-11, (1.35 ± 0.50) × 10-11, and 〈 10-12 cm3/molec·sec, respectively.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550090109
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  • 194
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    The decomposition of dimethyl peroxide and the rate constant for CH3O + O2 → CH2O + HO2 (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 9 (1977), S. 31-53 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The decomposition of dimethyl peroxide (DMP) was studied in the presence and absence of added NO2 to determine rate constants k1 and k2 in the temperature range of 391-432°K: \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{rcl} {{\rm DMP}} & \stackrel{1}{\longrightarrow} & {2{\rm MeO}} \\ {{\rm MeO + DMP}} & \stackrel{2}{\longrightarrow} & {{\rm MeOH + CH}_{\rm 2} {\rm O} + {\rm MeO}} \\ \end{array} $$\end{document} The results reconcile the studies by Takezaki and Takeuchi, Hanst and Calvert, and Batt and McCulloch, giving log k1(sec-1) = (15.7 ± 0.5) - (37.1 ± 0.9)/2.3 RT and k2 ≈ 5 × 104M-1· sec-1. The disproportionation/recombination ratio k7b/k7a = 0.30 ± 0.05 was also determined: \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{rcl} {{\rm MeO} + {\rm NO}_2 (+ {\rm M})} \stackrel{7a}{\longrightarrow} & {{\rm MeONO}_{\rm 2} (+ {\rm M})} \\ {{\rm MeO} + {\rm NO}_2} \stackrel{7b}{\longrightarrow} & {{\rm CH}_{\rm 2} {\rm O} + {\rm HONO}} \\ \end{array} $$\end{document}When O2 was added to DMP mixtures containing NO2, relative rate constants k12/k7a were obtained over the temperature range of 396-442°K: \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{rcl} {{\rm CH}_{\rm 3} {\rm O} + {\rm O}_2} \stackrel{12}{\longrightarrow} & {{\rm CH}_2 {\rm O} + {\rm HO}_{\rm 2}} \\ \end{array} $$\end{document} A review of literature data produced k7a = 109.8±0.5M-1·sec-1, giving log k12(M-1·sec-1) = (8.5 ± 1.5) - (4.0 ± 2.8)/2.3 RT, where most of the uncertainty is due to the limited temperature range of the experiments.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/kin.550090105
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  • 195
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    The deprotonation of internally hydrogen-bonded acids. Mechanistic conclusions from the influence of general bases (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 9 (1977), S. 1-12 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions between alizarin yellow G and six different bases B (including OH-) and between tropaeolin 0 and eight different bases have been investigated at 25°C and an ionic strength of 0.5M, using the temperature-jump method. From the form of the log kB versus ΔpK curves it is concluded that for alizarin yellow G the observed relaxation time is due chiefly to a diffusion-controlled reaction between the base and that fraction which is present in the “open” non-hydrogen-bonded form, whereas for tropaeolin 0 the base attacks the hydrogen bridge.The dissociation constants for the internally bound hydrogen have been measured under the same conditions of temperature and ionic strength, using a spectrophotometric method.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550090102
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  • 196
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    Reaction of atomic oxygen with cyclopentadiene (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 9 (1977), S. 67-81 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of 1,3-cyclopentadiene (CPD) with ground-state atomic oxygen O(3P), produced by mercury photosensitized decomposition of nitrous oxide, was studied. The identified products were carbon monoxide and the following C4H6 isomers: 3-methylcyclopropene, 1,3-butadiene, 1,2-butadiene, and 1-butyne. The yield of carbon monoxide over oxygen atoms produced (φCO) was equal to the sum of the yields of C4H6 isomers in any experiment. φCO was 0.43 at the total pressure of 6.5 torr and 0.20 at 500 torr. We did not succeed in detecting any addition products such as C5H6O isomers.It was found that 3-methylcyclopropene was produced with excess energy and was partly isomerized to other C4H6 isomers, especially to 1-butyne. The excess energy was estimated to be about 50 kcal/mol.The rate coefficient of the reaction was obtained relative to those for the reactions of atomic oxygen with trans-2-butene and 1-butene. The ratios kCPD+O/ktrans-2-butene+O= 2.34 and kCPD+O/k1-butene+O = 11.3 were obtained.Probable reaction mechanisms and intermediates are suggested.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/kin.550090107
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  • 197
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    Energy transfer in unimolecular reactions at high temperatures (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 9 (1977), S. 387-398 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The application of modern theories of energy transfer to unimolecular reactions taking place at very high temperatures is discussed. It is shown that the efficiency of energy transfer for both reactant-reactant and reactant-inert diluent collisions may be substantially smaller than the values determined experimentally at lower temperatures. Consequently at high temperatures unimolecular falloff effects, particularly in some shock-tube measurements, may be greater than has been believed hitherto.The application of these calculations to the unimolecular reactions of cyclopropane, cyclobutane, and cyclohexene at temperatures around 1300°K is discussed, and it is shown that under shock-tube conditions the apparent first-order rate coefficient may be at least ten times less than the high-pressure limiting value.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550090308
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  • 198
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    Electronic Resource
    High-temperature pyrolysis of dimethyl ether (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 9 (1977), S. 471-479 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of pyrolysis of dimethyl ether wexre studied in an adiabatic flow reactor at temperatures between 790 and 950°C. The unimolecular rate constant for the initiating step CH3OCH3 = CH3O + CH3 was found to be k1 = 2.16 × 1015e-76,600/RTsec-1. Aspects of the kinetic mechanism are discussed and a system postulated to account for the high-temperature products.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550090314
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  • 199
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    Masthead (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 9 (1977) 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550090201
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  • 200
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    Kinetics of gas-phase addition reactions of methyl radicals. I. Addition to ethylene, acetylene, and benzene (1977)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 9 (1977), S. 185-200 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions have been studied by a mass-balance method involving the photolysis of small amounts of biacetyl in the presence of a large excess of isobutane containing a small proportion of the unsaturated substrate. The following Arrhenius parameters have been derived: TextTemperatureElog ArangeReaction(kcal/mol)(1./mol·sec)(°K)ĊH3 + C2H4 → Ċ3H77.3 ± 1.08.32 ± 0.5350 - 500ĊH3 + C2H2 → Ċ3H57.7 ± 1.58.79 ± 0.8379 - 487ĊH3 + C6H6 → C7H97.6 ± 1.08.79 ± 0.5372 - 484The results for methyl addition to ethylene are based on previous determinations by other techniques as well as the present studies. The results for methyl addition to acetylene and benzene are derived solely from the present experiments and are calculated relative to a rate constant of log k2(l./mol·sec) = 7.42 - (7.1/θ) for the reference reaction (2), ·H3 + (CH3)3CH → CH4 + ·4H9.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550090204
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