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  • 1970-1974  (2,178)
  • 1971  (2,178)
  • Polymer and Materials Science  (2,119)
  • Computational Chemistry and Molecular Modeling  (59)
  • Nuclear reactions
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Material
Years
  • 1970-1974  (2,178)
Year
Keywords
  • 101
    Electronic Resource
    Electronic Resource
    Molecular weights and hydrodynamic properties for homogeneous native DNA, derived from diffusion, sedimentation, and viscosity measurements on polydisperse samplesPresented in part at Symposium, Transportvorgänge in verdünnten Polymerlösungen und ihre Anwendungen, Dresden, April 30, 1969. (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 285-307 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The diffusion, sedimentation, and viscosity behavior of native DNA has been studied as a function of molecular weight absolutely determined by diffusion and sedimentation measurements between 106 and 20 × 106 Daltons. Only data for monodisperse subfractions of the polydisperse DNA samples investigated have been compared. They were derived by means of calculations based on individual sedimentation constant distribution and polymer parameters. The inconstancy of these parameters for the semi-rigid DNA molecules over the range of different sub-fractions of the polydisperse samples has been taken into account. A detailed description of the corresponding mathematical background as well as of the diffusion measurements has been given in the two preceding papers. For the homologous series of monodisperse native DNA molecules, three-parameter equations have been determined representing the s0-[η], s0-M, and [η]-M relations as well as the D0-s0 and D0-M interdependence over the entire molecular weight range of interest. Furthermore a simple equation is given describing the molecular weight dependence of the Mandelkern-Flory-Scheraga parameter β in terms of s0 and [η]. The asymptotic value β∞ has been determined, primarily by measurements at finite molecular weights, to be 2.39 × 106, resulting in β values near 2.50 × 106 at M = 108 Daltons. The hydrodynamic properties of our two calf thymus DNA samples of highest molecular weight proved to be influenced by residual protein interactions resulting in a more compact conformation. Further data are given demonstrating the influence of the individual polydispersity of the investigated samples on diffusion constant and molecular weight averages.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100206
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  • 102
    Electronic Resource
    Electronic Resource
    Potentiometric and circular dichroic measurements of poly(L-glutamic acid) in aqueous solutions of organic and inorganic electrolytes at ambient temperature (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 357-377 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Titration of an aqueous solution of sodium poly-L-glutamate with a strong acid usually produces turbidity and precipitation before the equivalence point is reached. In 1M sodium p-toluenesulfonate and 1M sodium methylcyclohexanesulfonate aggregation was delayed for days to months. In very concentrated tetra-n-butylammonium chloride and bromide the polymeric acid dissolved and could be titrated with NaOH. However, potentiometric titration curves in these solutions did not yield information (by way of plots of apparent pK versus the degree of neutralization) about the helix-to-coil transition of the polymer. It was argued in addition that the apparent pK of a weak polyelectrolyte should not be calculated from titrations in concentrated salt solutions since it is a mixed or composite quantity. It contains not only the effect of the salt on the dissociation of the weak electrolyte but its effect on the activity coefficient of hydrogen ions as well.Circular dichroic spectra were therefore measured a t various degrees of neutralization of poly(L-glutamic acid) in a number of aqueous salt solutions and mixtures of organic solvents with water. It was found that the undissociated polymer in the concentrated methylcyclohexanesulfonate and quaternary ammonium halide solutions had the spectrum of a right-handed α helix. The n → π* band at 222 mμ was used as a measure of the fraction of polymer in the helical conformation. The value of - Δε for the undissociated polyacid in these organic electrolyte solutions was 11.4. By means of this value and a number of assumptions, the fraction of helix (fh) as a function of α, the degree of polyacid neutralization, was calculated for the different solvent mixtures. An empirical equation was used to describe the variation of fh with α, fh = 1/(1 + e-a+bα), in which b represents the degree of cooperativeness of the transition, and a is a measure of the effect of the medium on the onset of the transition. The values of b did not differ very much from one another, suggesting that the cooperativeness of the transition was not sensitive to changes in the medium. On the other hand, the value of a (or its equivalent, the value of α at the halfway point in the transition) was more dependent on the solvent. Comparisons of these results with those of some other workers were made by means of the empirical equation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100211
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  • 103
    Electronic Resource
    Electronic Resource
    Relation between Mw, Mn and M(swDA), M(swDw) and M(sη) (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 411-416 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100215
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  • 104
    Electronic Resource
    Electronic Resource
    Dielectric relaxation measurements as a tool for studying the kinetics of the helix-coil transition of poly (γ-benzyl L-glutamate) (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 417-419 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    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/bip.360100216
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  • 105
    Electronic Resource
    Electronic Resource
    Interaction of proflavine and 9-aminoacridine with DNA at temperatures below and above the melting temperature (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 399-410 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The influence of temperature on the binding of 9-aminoacridine and of proflavine to E. coli DNA in 10-3M NaCl solution has been determined by a spectrophotometric technique. The inadequacy of the expression normally used for the determination of the extent of binding is discussed with reference to measurements at temperatures above which dissociation of the double helix occurs. A method of determining the relative extents of binding to native and denatured DNA at elevated temperatures is described.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100214
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  • 106
    Electronic Resource
    Electronic Resource
    Announcement (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 421-421 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100217
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  • 107
    Electronic Resource
    Electronic Resource
    On the helix-coil equilibrium in two- and three-stranded complexes involving complementary poly- and oligonucleotides (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 423-423 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100218
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  • 108
    Electronic Resource
    Electronic Resource
    Molecular orbital calculations on the conformation of polypeptides and proteins. V. Conformational energy maps and stereochemical rotational states of aliphatic residues (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 491-511 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The quantum-mechanical calculations by the PCILO method on the conformation of amino acid residues of proteins have been extended to the valyl, leucyl, and isoleucyl residues. In distinction to the earlier “empirical” computations, the quantum-mechanical results indicate very similar energy contours for the stable conformations of the three residues. Their general outline is also similar to that of the alanyl residue, although reduced by about 25%. Contrary to the “empirical” computations, the present results predict that the region corresponding to the α-helix should be one of great stability for the three residues and in particular for the valyl residue. The quantum-mechanical results are in excellent agreement with the experimental conformations of the aliphatic residues in lysozyme and myoglobin. Their prediction as to the ready availability of the valyl residue in the α-helical conformation agrees moreover with Ptitsyn's statistical evaluation of the participation of this residue in the inner turns of the helical regions in six globular proteins. The maximum conformational space allowed for the aliphatic residues is somewhat smaller than that allowed for the aromatic ones, while the minimum conformational space (region of stability common to all the residues) is similar in both groups.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100306
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  • 109
    Electronic Resource
    Electronic Resource
    Experimental thermodynamics of the helix-random coil transition. IV. Influence of the base composition of DNA on the transition enthalpy (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 513-522 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The helix-coil transition of DNA of various base compositions has been followed by measuring the heat capacity and the ultraviolet absorption as a function of temperature through the transition region. The results of these measurements indicate that the transition enthalphy ΔH for a given pH value and salt concentration depends considerably on the base composition of the various DNA samples. The values of the transition enthalpies vary from ΔH = 7.73 kcal/mole base pair (MBP) for 31% GC base pairs to ΔH = 8.52 kcal/MBP for 72% GC base pairs. The results of the heat capacity measurements are discussed in relationship to the theoretical models suggested by various authors. Some peculiarities of the measured heat capacity versus temperature curves are reported. The correlation between these peculiarities and the results of the transcription experiments of DNA is discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100307
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  • 110
    Electronic Resource
    Electronic Resource
    Infrared investigation of poly-L-histidine structure dependent on protonation (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 711-719 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly-L-histidine (PLH) films at different degrees of protonation were produced mid subjected to infrared spectroscopic investigation (range 4000-650 cm-1). In addition, the N-deuterated film spectra were plotted. The amide II and III bands show that the peptide group is present in the trans form. The amide I and II bands show that at 0% and 50% protonation the PLH occurs as an α-helix and at 100% protonation as a random coil with some ranges in β structure. At 0% and 50% protonation, no hydration water is bound to the backbone. At 0% protonation all NH groups are linked to each other or to water molecules via hydrogen bonds. At 50% protonation NH+ċN bonds form between the imidazole rings. These protons are present in continuous energy level distribution. Such bonds with tunneling protons are extremely polarizable and between these bonds may act proton dispersion forces. The Cl- ions are bonded to the NH groups of the imidazole groups. The hydration water is bonded to the Cl-- ions and to the NH groups. At 100% protonation, hydration water is bonded also to the CO groups of the backbone. The NH groups of the backbone, like those of the rings, endeavor especially in the dry state to bond to the Cl- ions. This leads to a strong steric constraint of the random coil.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100409
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  • 111
    Electronic Resource
    Electronic Resource
    A cooperative transition between two helical conformations in a linear system: poly-L-proline I ⇌ II. II. Kinetic studies (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 721-737 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformational transition between the two helical forms I and II of poly-L-proline serves as an experimental model for the study of the kinetic, behavior of cooperative systems. The slow I ⇌ II conversion after a sudden perturbation of the solvent composition was followed polarimetrically. The dependence of the mean relaxation times on chain length and the degree of conversion was compared with Schwarz's theory. In addition, a description of the entire relaxation curves was possible in three special cases: all-or-nothing, small perturbations of the I ⇌ II equilibrium in long chains, and conversions which start off with molecules completely in one or the other conformational state. The mathematical model on which the theory is based contains only one more adjustable parameter than the equilibrium model, but it adapts to the experimental results surprisingly well. The present kinetic results and equilibrium measurements on this system are described by the same values of those parameters which are common to both models. The found value of the rate constant of the propagation step, i.e. the cis ⇌ trans isomerization of a peptide bond at an existing I-II junction, agrees with the rate of isomerization in N,N-dimethylacetamide reported in the literature. The rate of nucleation is up to 105 times smaller than the rate of propagation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100410
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  • 112
    Electronic Resource
    Electronic Resource
    Optical rotary dispersion of mucopolysaccharides III. Ultraviolet circular dichroism and conformation al specificity in amide groups (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 739-751 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism of glycosaminoglycans and ganglioside in distilled water are described, showing two bands in the region of amide and carboxyl transitions. The first, negative hand is common to all polymers and the amino sugar derivatives. The characteristics of the second band depend upon polymer structure. Those containing 4-1-linked amino sugars show a second, positive, resolved band about 190 mμ, while those with 3-1-linked amino sugars show a second, negative band less resolved from the first usually ≤185mμ, but clearly centered at 188mμ for dermatan sulfate. Ultraviolet optical absorption from 300 to ∼183 mμ showed inflection regions around 190 mμ for most compounds.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100411
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  • 113
    Electronic Resource
    Electronic Resource
    Stereoselective polymerization of γ-Benzyl Glutamate NCAPaper presented to the joint CIC/ACS Symposium on Kinetics and Mechanism of Stereoregular Polymerizations, Toronto, Canada, May 1970. (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 753-765 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of γ-benzyl glutamate NCAs has been investigated. The results indicate that a coil-to-helix transformation is not responsible for the kinetic data. The results were rationalized by assuming formation of polymer aggregates coupled with the stereoselective adsorption of monomer onto growing polymer prior to reaction. From kinetic data a ratio of equilibrium constants for adsorption was determined. Independent data confirmed the assumption that adsorption of monomer onto polymer occurred. Equilibrium constants were evaluated, and their ratio was found to be comparable with that obtained from the kinetic data.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100412
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  • 114
    Electronic Resource
    Electronic Resource
    Hydration of DNA: A neutron scattering study of oriented NaDNA (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 849-863 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A preliminary neutron-scattering study of wet-spun oriented NaDNA samples with various contents of H2O or D2O has been performed to obtain information about the hydration of NaDNA. The preferred orientation was in the direction of the crystallographic c axis. Perpendicular to this direction the samples could be regarded as poly-crystalline. It has been found that the preferred crystallite orientation was also reflected in the water structure. This fact, taken together with the small energy widths of the measured near-elastic peaks indicates that water molecules in the sample are relatively strongly bound to the DNA helix either directly or via other water molecules. Angular distribution measurements of elastically scattered neutrons were performed with the momentum transfer vector directed along and perpendicular to the DNA helix axis. Different Debye-Waller factors were obtained, indicating different water dynamics in the two directions. Comparison between the H2O and D2O measurements suggests that the difference is caused by motions of rotational nature. The shape of the frequency distribution function for the H2O molecules in the NaDNA sample was somewhat similar to that which has been measured in ice.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100509
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  • 115
    Electronic Resource
    Electronic Resource
    Dichroism of TMV in pulsed electric fields (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 865-882 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The linear dichroism induced in a solution of electrically anisotropic molecules by a pulsed electric field has been studied. Equations have been obtained which express the dichroism as a function of dipole moment, excess polarizability, field strength, and the angle α between the dipole moment and the transition moment for the absorption band. These expressions have been related to the experimentally observed difference signal in such a way that when the dichroism is measured as a function of field strength the permanent moment, excess polarizability and angle a can be determined.Experiments have been carried out on tobacco mosaic virus (TMV), which is similar in its properties to the theoretical model. The polarizability anisotropy and rotary diffusion constant for the monomer and dimer of TMV have been obtained from these experiments. In addition to the molecular parameters mentioned above, the saturated electric dichroism of the virus was measured as a function of wave length and the presence of an n-π* transition in the tryptophan spectrum was indicated.Further experiments measuring dichroism as a function of pH demonstrated the general denaturation of the virus at high pH (10-11) but also the existence of a stable fraction which is not fragmented even at the high pH involved.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100510
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  • 116
    Electronic Resource
    Electronic Resource
    The binding of Mg++ ions to polyadenylate, polyuridylate, and their complexes (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 2459-2490 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The binding of Mg ++ to polyadenylate (poly A), Polyuridylate(poly U), and their complexes, poly (A + U) and poly (A + 2U), was studied by means of a technique in which the dye eriochrome black T is used to measure the concentration of free Mg-. The apparent binding constant KX = [MgN]/[Mg++][N], N = site for Mg++ binding (the phosphate group of the nucleotide), was found to decrease rapidly as the extent of binding increased and, at low extents of binding, as the concentration of Na- increased in poly A, poly (A + U), and poly (A + 2U), and somewhat less so in poly U. Kx is generally in the range 104 〉 KX 〉 102. The cause of these dependences is apparently, primarily, the displacement of Na+ by Mg++ in poly U and poly (A + U) on the basis of the similarity of extents of displacement measured in this work and those measured potentiometrically. \documentclass{article}\pagestyle{empty}\begin{document}$$ \Delta H'{\rm v}.{\rm H}. = - R(\partial {\rm }\ln Kx/\partial 1/T)_\theta,\theta = \frac{{{\rm Mg}N}}{{N_t }} $$\end{document} was calculated and was found to approach zero as the concentration of Na+ increased. In poly U, poly (A + U), and poly (A + 2U) at low ΔH′ v.H. 〉 0, about + 2 kcal/“mole.” In poly A, also at low salt, ΔH′ v.H. ≈ -4 kcal/“mol” for the initial binding of Mg++, and increases to +2 kcal/“mol” at saturation. This enthalpic variation probably accounts for the anticooperativity in the binding of Mg++ not ascribable to the displacement of Na++.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360101209
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  • 117
    Electronic Resource
    Electronic Resource
    On the conformations of poly-N-methyl-L-alanine (PNMA) in solution (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 2581-2590 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High-resolution nuclear magnetic resonance spectra at 100 MHz have been obtained on poly-N-methyl-L-alanine in the chloroform-trifluoroacetic acid system under various conditions of solvent composition. Different spectra are observed for the CH3-Cα, Cα-H, and N-CH3 protons. On the basis of conformational analysis an interpretation of the NMR results was attempted.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360101217
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  • 118
    Electronic Resource
    Electronic Resource
    Evaluation of RNA conformation from circular dichroism and optical rotatory dispersion data (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 2607-2614 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analysis of optical rotatory dispersion and circular dichroism of RNA is described which leads to an estimate of the degree of base pairing. By the use of new standards for the double-helical parts of the molecule, based on data for two-stranded viral RNA species, a good fit between calculated and observed curves can be achieved. Where data are available the results of analyses of optical rotatory dispersion and circular dichroism in general show satisfactory consistency.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360101220
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  • 119
    Electronic Resource
    Electronic Resource
    The effect of mercuric ion on the DNA-methylene blue complex (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 2625-2628 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    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/bip.360101224
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  • 120
    Electronic Resource
    Electronic Resource
    Electric field effect on poly-alanine and poly-hydroxyproline film conformation (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 2645-2648 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360101228
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  • 121
    Electronic Resource
    Electronic Resource
    Gaussian expansion method for molecular integrals of molecular properties (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 1-11 
    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 finite Gaussian Expansion method for molecular integrals proposed by Taketa, O-ohata and Huzinaga has been extended to the integrals of molecular properties. The integral formulas of so-called moment, field and field gradient integrals have been derived. It has been numerically shown that in order to evaluate the field and the field gradient integrals based on Slater type orbitals, eight- or ten-term Gaussian expansions are sufficient but this method fails to attain sufficient effective numbers for the moment integrals.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/qua.560050102
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  • 122
    Electronic Resource
    Electronic Resource
    Time-dependent quantum theory III. Model for vibrational relaxation in crystals (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 239-263 
    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 one-dimensional model consisting of a “diatomic” spring attached on one side to a rigid wall and on the other side to a linear array of mass-springs is proposed as a model for the vibrational relaxation of small solute molecules in host lattices. A modification allowing a change in the equilibrium internuclear extension of the diatomic spring is also incorporated. The Hamiltonian divides naturally into pure diatomic, pure linear crystal, and the two mixed perturbation terms, one giving rise to stepwise vibrational cascade damping accompanied by phonon emission, and the other process, lattice relaxation, giving rise to phonon emission without any change of the quantum number of the diatomic spring. The cascade damping rate for a diatomic spring with a frequency less than the the maximum frequency of the linear crystal is calculated to second-order, and it is shown that the perturbation series converges in this range.An upper bound to the cascade damping rate for a diatomic spring with a frequency greater (i.e., 4.5 ×) than the cut-off frequency of the linear crystal is determined to be very small, λ ≦ 104 sec -;1.The rate for the lattice relaxation process corresponds to a line-width λ = 6 cm -1 at 0K.An explanation for the thermal quenching of the low-temperature luminescence of SO2 is based upon induced cascade-phonon emission.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050302
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    On the theoretical foundation of Walsh's rules of molecular geometry in terms of the Hellmann-Feynman theoremAbstracted from part of a D.Phil. thesis submitted by B. M. Deb to the University of Oxford, 1969. (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 411-434 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new interpretation of the ordinate in a Walsh diagram for a polyatomic molecule is suggested in terms of the Hellmann-Feynman theorem. This makes use of the fact that in a single-configurational MO wave function the total one-electron density is the sum of individual densities in the occupied orbitals. Walsh-type diagrams have been constructed for three different molecules, water, ammonia and hydrogen peroxide.In H2O and NH3 calculation of the force, and thus of the energy, in terms of the valence angle, is made on the assumption that the central (heavy) atom is kept fixed while each of the lighter atoms moves in a plane containing the principal symmetry axis and the relevant bond, in a totally symmetric fashion; for H2O2 the two oxygen atoms are kept fixed.The angular correlation diagrams obtained reproduce the general features of those obtained by plotting Hartree-Fock MO energies as functions of the valence angles. The conclusion emerges that the force formulation provides a satisfactory pictorial basis for understanding molecular geometry in terms of the balance between the electron-nucleus attractive forces resulting from the charge densities in the occupied MO'S, and the nuclear repulsive forces. However, in the absence of highly accurate charge distributions such an approach is unsuitable for the quantitative prediction of molecular quantities such as valence angles, force constants or energy barriers.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050406
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    Masthead (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971) 
    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.560050501
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  • 125
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    Self-consistent pseudo-eigenvalue equations in parametric charge-dependent MO methods (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 477-478 
    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.560050411
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  • 126
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    All-electrons band structure of Polyene (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 557-563 
    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 work, we report an all-electron SCF-LCGO-CO computation for the ground state wave-function of an infinite polyenic chain. This work demonstrates that ab initio calculations on the electronic structure of polymers become actually feasible. Our results are compared with previously obtained semi-empirical ones.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050509
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    Angular dependence of the retarded dispersion energyThis research was supported in part by a grant from the National Research Council of Canada. (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 549-556 
    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 Casimir-Polder retarded dispersion energy is calculated for non-symmetric molecules and the energy is expressed in terms of body fixed axes for the dipole transition moments on each molecule. In the special case of molecules with cylindrical symmetry the potential energy is given in terms of the transverse and longitudinal polarizabilities and in terms of the angles defining the orientation of the axes of the molecules with respect to the intermolecular direction. In the limit of no retardation (R ≪ λ) the result becomes that of London and in the opposite limit of full retardation at large R the potential energy tends to that of Craig and Power.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050508
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  • 128
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    The mechanism of binding of polycyclic aromatic hydrocarbons to nucleic acids: A theoretical investigationThis work was supported by grant number CR 66-236 of the Institut National de la sante et de la recherche medicale (intergroupe cancer et leucemie). (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 575-582 
    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 kinetic model employing calculated atom and bond localization energies to approximate relative activation energies of reaction is used to analyse previously obtained experimental results for in vitro and in vivo chemical binding of polycyclic aromatic hydrocarbons to nucleic acids. It is found that in vitro linkage of hydrocarbons to DNA induced by a microsomal hydroxylating system is compatible with mechanisms involving either attack at the most reactive hydrocarbon center or attack at the most reactive hydrocarbon bond. Independent evidence leads us to favor the former mechanism. Further, the limited experimental data for in vivo linkage of hydrocarbons to DNA is found to be consistent with a model involving attack at the most reactive bond of the molecule: the “K region”. This model is supported by a close parallelism found between extent of hydrocarbons bound to DNA in vivo and the experimentally determined relative reactivities of their K regions.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560050511
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  • 129
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    The generalized separated electron pair model. II.Taken in part from a thesis submitted to the University of Toronto in partial fulfilment of the requirements for the Ph.D. degree. An application to NH4+, NH3, NH2-, NH2- and N3- (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 605-635 
    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 Separated Electron Pair (SEP) model (Strongly Orthogonal Geminals) and methods for its systematic extension has been applied to the series: NH4+, NH3, NH2-, NH2- and N3-. On going from NH4+ to N3-, the SEP model, in its most general form, recovers 85-75% of the intrapair correlation energy and 60-55% of the interpair correlation energy obtainable with the given basis set. The best wave functions for each species recovered about 45-50% of the total empirical correlation energy which is expected to be very close to the basis set limit. It was apparent that the SEP model yields a set of one-electron functions that are very useful for further improvement of the wave function. This fact apparently remains true even when the SEP model itself gives very poor energies.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050603
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  • 130
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    Theory of intermolecular forces. I. On the inadequacy of the usual Rayleigh-Schrödinger perturbation method for the treatment of intermolecular forces (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 273-296 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The problem of intermolecular interaction is examined by using spatial wave functions and the theory of permutation groups. In the special case of interacting 2-electron systems it is proven that the Rayleigh-Schrödinger perturbation method, when starting from the ground state of the unperturbed system, could only give the physically inadmissible mathematical ground state of the complex (totally symmetric spatial eigenfunction). Then this property is considered in the case of arbitrary interacting systems and a general proof is proposed. From these results a general explanation of the inadequacy of the Rayleigh-Schrödinger expansion for the treatment of short range intermolecular interaction is proposed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050304
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  • 131
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    Optimized linear combinations of simple exponentials for atomic systems (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 319-333 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hartree-Fock wave functions for the He and Be isoelectronic sequences of ions are calculated using orbitals which are linear combinations of simple exponential functions. By a full optimization of the exponents and coefficients close approximations to the HartreeFock energies were obtained. To the same order of accuracy the resulting Hartree-Fock orbitals require fewer basis functions than used previously. A number of difficulties which arise in the numerical procedures as the size of the basis set is increased are analysed in detail. Similar results are obtained for the Li sequence using the Unrestricted HartreeFock method with and without projection.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050307
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  • 132
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    Self consistent molecular orbital calculations on polyatomic molecules: Gaussian approximation for two-electron integrals (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 497-503 
    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 MO-LCAO-SCF treatment is performed on water, ammonia and methane using a recently proposed approximate method.The procedure is found capable of predicting total and orbital energies in close agreement with the results of accurate computations using double ζ basis sets of Slater type orbitals.A comparison is made with the results of similar approximate ab initio procedures.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050503
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    Poisson equation for molecular exchange, hybrid and coulomb electron repulsion integrals (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 505-512 
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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 various multicenter exchange, hybrid and Coulomb electron repulsion integrals that occur in molecular quantum mechanics are shown to satisfy a Poisson equation in which an overlap integral plays the role of a source distribution function. Two-, three-and four-center exchange integrals arise from four-center source functions; two- and three-center hybrid integrals arise from three-center distributions; and one- and two-center Coulomb integrals have two-center sources.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560050504
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    Natural orbital iterations for the ground state of nitric oxideThis work has been partially supported by Grant No. AF-AFOSR-69-1714 from the Air Force Office of Scientific Research. (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 539-548 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method for the use of natural orbital iterations in limited CI calculations is discussed. This method is then applied to the ground X2II state of the nitric oxide molecule at its experimental equilibrium internuclear separation to yield the total energy, dipole moment, spin densities at each nucleus, and approximate natural spin orbitals for this molecule.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050507
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    Masthead (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971) 
    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.560050601
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  • 136
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    Time-dependent quantum theory I. An absorber in an intense radiation field (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 13-34 
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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: A function analogue of the formal operator theory of Goldberger and Watson for the decay of prepared states is developed with a modification that permits treatment of degenerate, interacting intermediate states. The theory is applied to the problem of absorption of radiation by an absorber in a very intense monochromatic beam. In particular, a simple two-level absorber in a resonant monochromatic beam of sufficient intensity to induce transitions from the ground state at a rate exceeding the spontaneous emission rate from the excited state, but still lying well below the optical frequency characterizing the transition, is investigated with the conclusion that the absorption cross-section falls off with the one-half power of the incident intensity. Conditions for the possible experimental verification of this result are presented.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050103
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    A computational form for löwdin's alpha functionPart of this work was performed at the University of California, Riverside, where it was supported by a grant from the National Science Foundation. (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 111-113 
    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.560050108
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  • 138
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    On the theory of electron correlation in atoms and molecules: Relation between cluster expansion theory and the correlated wave functions method (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 119-130 
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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 relation between the cluster expansion theory of many electron wave functions and the correlated wave functions method is established. In this way, the theoretical basis of the method is elucidated and the approximations involved in its application become apparent. General forms of the correlated wave function, differing in certain important respects from that form usually assumed, are derived.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050202
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  • 139
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    Analysis of reduced density matrices in the coordinate representation. II. The structure of closed-shell atoms in the restricted Hartree-Fock approximationThis work was supported in part by Research Grant GP-7910 from the National Science Foundation. (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 189-214 
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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 electron density and the Fermi hole of the ground states of the atoms He, Be, Ne, Mg, Ar, Ca, Zn, and Kr are studied in the restricted Hartree-Fock approximation. The use of single Slater-type orbitals for the free atoms is also discussed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050206
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    Time-Dependent quantum theory. IV. Effect of lattice relaxation on the optical spectra (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 221-234 
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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 absorption and emission spectra of a diatomic “molecule” connected to an unstrained linear crystal are calculated for the circumstance where the diatomic undergoes a change of equilibrium internuclear separation in the electronic transition. The expansion (or contraction) of the diatomic results in a frequency dependent line-width in the customary Lorentzian expression, and is manifested in the absorption spectrum as an asymmetric tailing to the blue, and in the emission spectrum as an asymmetric tailing to the red. The interaction of the diatomic with the lattice also produces a blue-shift of the absorption spectrum and a red-shift of the emission spectrum. An important consequence of the asymmetry is the apparent loss of integrated intensity of the line. The striking similarity, both in the width and the over-all shape, of the emission line calculated here with those observed in the Vegard-Kaplan band of N2 dissolved in rare gas crystals is discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050208
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    The optimum projection technique in many-electron treatmentsSupported by the National Research Council of Canada. (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 297-309 
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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 optimum projection technique is the determination of the best function in the space spanned by a set off f(N, S) linearly independent antisymmetric space-spin eigenfunctions of S2 obtainable from a spatial function made of a product of N-independent orbitals. This is formulated in the spin-free framework. We consider several sets of predetermined orbitals for the lithium 2S state. Both the energy and spin-density are determined for each optimum projected function. The behavior of certain results is explained in terms of the “closeness” of the ls and ls′ split-shell core orbitals.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050305
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    On the energy difference between the lP and 3P states of the beryllium isoelectronic sequence (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 335-357 
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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: Wave functions of the 1S (ground state), 3P and 1P states for the beryllium isoelectronic sequence have been obtained in various approximations.The HF 2p orbitals for the 1P and 3P states are similar except for Be, where the 2p orbital is quite diffuse for the 1P state.The difference between the experimental E(1P) - E(3P) and the HF E(1P) - E(3P) is 0.62 eV for Be and 1.17 ∼ 1.40 eV for B+ ∼ F5+. The disagreements are attributed to the correlation effects between the 2s and 2p electrons. This is confirmed by ci calculations.It is shown that a limited basis SCF calculation reproduces the above feature of the HF results if we treat the orbital exponents as the variational parameters. The use of the Slater values for the orbital exponents is shown to be inadequate especially for the Be 1P state.The conclusions of this paper will be useful for discussing the V-T separations of H2 and C2H4.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560050308
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    The electronic correlation problem and loge localization (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 395-409 
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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 model of complete loge localization is employed here to develop a practical method for handling correlation effects in atomic and molecular many electron systems. Intraloge correlation is dealt with by an independent variational treatment of pair functions which are continuous and vanish outside a given loge. It is shown that in the context of the model it is possible to compute pair correlation energies for localized single and double bonds in molecules by evaluating only modified atomic integrals. We bypass in this manner the evaluation of multicenter integrals necessary in other formalisms. In addition, the corrections to the model are discussed and in particular it is shown that part of the interloge correlation effects are already described by the loge localized wave function.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050405
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    High orders corrections to the Van der Waals-London forces. II. Interaction of two molecules with isotropic polarizabilities (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 455-467 
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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 infinite summation of intermolecular ring diagrams is extended to any pair of interacting molecules with isotropic polarizabilities. The calculation no longer requires the use of a minimal basis set. The polarizabilities α,α′ may be factorized at all orders, and an expression is derived, which gives modified Van der Waals energies. For heavy atoms the series converges if αα′/R6 is smaller than 1, R being the interatomic distance. This inequality is easily satisfied for the Van der Waals distances, and in practice the correction due to the high orders of the perturbation expansion remains weak. The role of the EPV diagrams and the connection with a configuration interaction treatment are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050408
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    A theoretical investigation of the singly excited two-electron atomic states 1s2s3S and 1s3s3S (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 583-598 
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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 singly-excited two-electron states 1s2s 3S and ls3s 3S have been investigated by means of the variational perturbation theory procedure. The wave functions have been constructed as linear combinations of Hylleraas terms with hyperbolic factors in t, and the results obtained by carrying the computations through to 10th perturbation order and with 36(37)- 57(58)- and 85(86)-term basic sets, respectively, are reported. These results compare favourably with the corresponding best values from previous conventional variational calculations.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050512
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    A self-consistent variation-perturbation theory for open shell atomic systems: Calculation of polarizabilities and shielding factors (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 637-646 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper a fully coupled variation-perturbation theory has been introduced for handling open-shell atomic systems in the presence of static perturbations. The static dipolar and quadrupolar polarizabilities and shielding factors for Li, Be+, B2+, B, C+, Na and Al have been calculated and compared with available results. Important sources of discrepancies in previous calculations of shielding factors have been noticed and critically examined. The dipolar shielding factors calculated in this paper show satisfactory agreement with the theoretical N/Z ratio. In the absence of any theoretical test for the quadrupolar shielding factor, the accuracy of the calculations of γ∞, should be judged in the light of the accuracy of the corresponding β∞ values.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050604
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    High orders corrections to the Van der, Waals-London forces. I. A model problem: Two interacting hydrogen molecules is the minimal basis set (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 435-453 
    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 classical intermolecular Rayleigh-Schrödinger perturbation expansion is used with a finite basis of simple products of single determinants. For two hydrogen molecules with a minimal basis set, one shows that the ring and ladder diagrams dominate the perturbation series. The contributions of the purely intermolecular convex and concave ring diagrams are summed at all orders. The mixed ladder-ring diagrams are also included. The series converges if the norm of the first order perturbed wave function is smaller than ½. The summation multiplies the Van der Waals-London forces by an explicit factor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050407
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  • 148
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    Announcements (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 475-475 
    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.560050410
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  • 149
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    Increased-valence formulae and the bonding of oxygen to haemoglobin (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 479-495 
    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 molecular orbital configuration for the ground-state of O2 generates the valence formula . “Increased-valence” formulae for triatomic and polyatomic molecules have been developed recently. In them, more electrons participate in bonding than is possible for the familiar valence-bond formulae. Using oxyhaemoglobin as an example of an oxygen carrier, various increased-valence formulae are generated for the FeO2 groups. In the low-energy formulae, the iron is bonded to the above valence formula for O2. Therefore, in contrast to the bonding schemes of Pauling and Coryell, Griffith and Weiss, little reorganization of O2 need occur on formation of HbO2. This conclusion is independent of the mode of co-ordination of iron to the O2.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050502
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  • 150
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    Bounds to second-order perturbation energies (particularly dispersion) for excited states (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 525-537 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Upper and lower bound expressions are derived to the second-order energy relating to an unperturbed degenerate excited state in those cases where both the first-order energy and the off diagonal matrix elements in the secular equation vanish, making use of the partitioning technique, operator inequalities and inner projection approach. These expressions, which involve an arbitrary basis, are then developed to yield reasonably good bounds to van der Waals dispersion energies for systems of the type H (first excited state)  -  other atom b (ground state). The particular choice of basis used in the development yields the latter bounds easy to evaluate by expressing them in terms of the ground state sum rule values, S(k) of atom b. This same choice is also utilized in Lindner and Löwdin's expressions [1] to obtain bounds to systems of the type H (ground state)  -  other atom b (ground state) that are comparable to those found by other more elaborate semi-empirical methods.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050506
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  • 151
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    Frequency distribution of radiation emitted from excited atomic systemsThis research was supported in part by ARPA under contract AF30(602)-4277. (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 565-574 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: General expressions for the time-dependent probability amplitudes of the quantum states of two arbitrary, interacting atoms are calculated when one atom is initially in an excited p state and the other atom is in an s ground state. The lifetimes of the excited states and the line shape of the emitted radiation are obtained as functions of both the atomic separation and the energy difference between the excited states of the two atoms. The emission line shape is shown to be doubly peaked and to agree with the line shape of the radiation scattered by a system of two interacting atoms. The expressions for the lifetimes of the excited states are found to be identical to those obtained for the radiation scattering situation.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560050510
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  • 152
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    Origin of the irrational part contained in the angular numerical factors of matrix elements of the Coulomb operator (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 599-603 
    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 means of second quantization formalism and angular momenta coupling techniques, we show the reason why the irrational part of the coefficients of the Slater integrals Rk(ab, cd) in the expression \documentclass{article}\pagestyle{empty}\begin{document}$ (\Psi |\sum\limits_{i 〈 j} {e^2 /r_{ij} |\Psi } ') $\end{document} is common to all values of k, a, b, c, d, and depends only on (Ψ∣ and ∣Ψ′).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050602
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  • 153
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    Symmetry properties of one- and two-electron molecular integrals (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 657-668 
    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 maximum numbers of distinct one- and two-electron integrals that arise in calculating the electronic energy of a molecule are discussed. It is shown that these may be calculated easily using the character table of the symmetry group of the set of basis functions used to express the wave function. Complications arising from complex group representations and from a conflict of symmetry between the basis set and the nuclear configuration are considered and illustrated by examples.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050606
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  • 154
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    Continuous degeneracy and energy-localization of molecular orbitalsWork performed in the Ames Laboratory of the US Atomic Energy Commission, Contribution No. 2871. (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 683-697 
    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 energy-localization method is examined for continuous degeneracy using a grouptheoretic approach. Conditions for the degenerate orbitals are obtained and an enumeration of symmetry groups where continuous degeneracy may occur is given. It is found that the orbitals may be equivalent under operations not contained in the total symmetry group. An alternative explanation for the free rotation of the lone pairs in F2 is offered.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/qua.560050608
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  • 155
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    Announcement (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 115-115 
    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.560050109
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  • 156
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    Theoretical study of a 1 : 1 complex between quinone and hydroquinone (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 101-110 
    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 Variable Electronegativity Pariser-Parr-Pople method has been successfully applied to calculate the potential energy curve for the formation of a 1: 1 complex between quinone and hydroquinone. A consistent evaluation of core and electronic repulsion integrals is important to obtain a meaningful curve. A computationally simple procedure has been suggested for separating interactions due to electron exchange between the components from other intermolecular interactions. In agreement with experimental deductions the preferred configuration for the quinone-hydroquinone complex is found to be one in which the molecules are in parallel planes with their C - O bonds parallel. The equilibrium separation between the molecular planes is found to be 2.3 Å and the stabilization energy in this position is 1.2 eV. In this equilibrium position forces due to electron exchange constitute the major contributing factor to the stability of the complex.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050107
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  • 157
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    Padé approximants to physical properties via inner projectionsSponsored in part by the Swedish Natural Sciences Research Council and in part by the Air Force Office of Scientific Research (OSR) Through the European Office of Aerospace Research (OAR) United States Air Force under Grant EOOAR-70-0073. (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 131-156 
    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 [N, M] Padé approximants to functions formally associated to power series expanssions are expressed in terms of expectation values of inverse matrices. These formulae, which can be derived by the inner-projection technique, lead to a simple analysis of the properties of serveral approximation methods and their inter-relationships, in particular Gaussian integration, continued factorization and Padé approximations, which are of current interest in the calculation of physical properties. A relation with Fredholm integral equations and expansions of the resolvent is also discussed.The use of operator inequalities in a systematic fashion is particularly convenient when both the function being approximated and the coefficients of the power series have physically meaningful expressions as moments of operators.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050203
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  • 158
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    Masthead (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971) 
    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.560050301
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  • 159
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    A perturbed generalized eigenvalue equation for the helium atom. II (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 387-394 
    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 Schrödinger equation for helium is written as a generalized eigenvalue equation which is solved for the ground state using perturbation theory. Two zero order equations are used and defined implicitly by specifying their eigenvalues and eigenfunctions. In both cases the eigenfunctions are taken to be the complete discrete set of products of eigenfunctions of the generalized eigenvalue equation for the hydrogen atom. To complete the definition the zero order eigenvalues are needed and two different intuitive choices are made. In the better of our two calculations an energy of -2.9014 a.u. is obtained for helium using the perturbation theory to second order.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050404
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  • 160
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    On the Mavroyannis-Stephen relativistic long-range interaction energy term between optically active molecules (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 469-473 
    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 relativistic long-range intermolecular interaction energy term of Mavroyannis and Stephen is estimated for some amino acids by using optical rotatory dispersion data and for hexahelicene by using theoretical values of excitation energies and rotational strengths. The result shows that the interaction energy may be significant for the interaction between some essentially dissymmetric chromophores such as hexahelicene, but that it is unimportant for other cases.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050409
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  • 161
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    A note on the theory of interatomic long-range forces (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 478-478 
    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.560050412
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  • 162
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    Self-consistent calculation of excited 3P state wave functions of atoms (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 647-655 
    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 variation perturbation method in the Hartree-Fock scheme has been described to calculate excited 3P state wave functions of atoms. The starting wave functions are obtained from a study of the singularities in the dynamic polarizability calculation [1]. The 23P, 33P and 43P states of He, Li+, Be2+, B3+ and C4+ are studied. The results obtained are in satisfactory agreement with experimental values and with other accurate theoretical estimates.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050605
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  • 163
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    A comment on the super-secular-equation in a symmetry adapted basis (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 699-702 
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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 super-secular-equation has been introduced by Löwdin to discuss the Schrödinger equation in terms of a linearly dependent basis. The method is shown to be particularly simple when the basis is a symmetry adapted one. By expanding the secular equation a formula giving a good estimate of the eigenvalue is obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050609
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  • 164
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    Electronic absorption spectra for free hydrazyl radicals, their ionic forms and initial hydrazines (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 513-524 
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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 results of the calculations of π-π* transition energies of some free hydrazyl radicals, their ionic forms and initial hydrazines by the SCF-MO-LCAO method with restricted configuration interaction are presented. The comparison of the data obtained with the electronic spectra experimentally found, revealed that the absorption of radical solutions in the visible area was due to the electronic structure of radical molecules, the contribution of ionic forms to the absorption being negligible.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050505
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  • 165
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    Perturbational calculation of the exchange forces in the two lowest states of the hydrogen molecule (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 85-99 
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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 interaction energies in the ground (X1Σg+) and the first excited (b3Σu+)states of the hydrogen molecule were calculated using the modified Jansen and Byers Brown perturbation method. Calculations were performed for nine values of the internuclear distance R in the range 5 a.u. ≦ R ≦ 9 a.u. The present results were compared with the interaction energies calculated by four other perturbation methods as the expectation values of the H - E0 operator with the function accurate up to the first order. The results show that the method can give satisfactory values of the interaction energies.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050106
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  • 166
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    Analysis of reduced density matrices in the coordinate representation. I. Definitions and basic formulasThis work was supported in part by Research Grant GP-7910 from the National Science Foundation. (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 177-187 
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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 probability interpretation of density matrics is reviewed and certain quantities suggested for study by means of diagrams. The case of a “spin-symmetric ensemble” is further discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050205
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  • 167
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    On a formula of Braun and Rebane for variational bounds to overlap (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 215-220 
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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 recent formula of Braun and Rebane for variational bounds to overlap is shown to be closely related to the methods of Rayner and of Weinhold for the same problem, and is extended to give upper and lower bounds to overlap in both ground and excited states.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050207
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  • 168
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    Computation of LCAO wave functions for ground states of polymers and solids (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 67-84 
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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 LCAO form of the Hartree-Fock method is discussed in its application to crystals. General formulae are given for obtaining Fourier coefficient of electronic density (in direct space) as well as of the band structure (in momentum space). Finally, it is shown that in its LCAO form, Slater-Hartree-Fock equations are very simple and that this method is of interest for numerical applications. Special integrals occurring in this formalism are evaluated for a Gaussian basis in the last part of this paper.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050105
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  • 169
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    Masthead (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971) 
    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.560050201
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  • 170
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    Configuration interaction study of X-ray and fast electron scattering factors for light atomic systems (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 157-175 
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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 study of X-ray and fast electron scattering by light atoms and ions has been carried out in the first Born approximation. Coherent and incoherent scattering factors calculated with configuration interaction wave functions are compared with those obtained with Hartree-Fock wave functions. These configuration interaction wave functions involve only L-shell correlation. It is shown that the changes in the coherent scattering factors due to configuration interaction are not negligible and that the electron correlation effects on the incoherent scattering factors are important. Tables of coherent and incoherent scattering factors for light atomic systems are given.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050204
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  • 171
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    Theta-Function overlap approximation applied to the energy of cyclic polyenes (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 235-238 
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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.560050209
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  • 172
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    Effect of semi-empirical parameters on the triplet energy levels and triplet-triplet transition in benzene (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 265-272 
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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: Triplet energy levels and triplet-triplet transition in benzene have been calculated semi-empirically by considering CI up to and including doubly excited configurations and using various values of the core resonance and electron repulsion integrals. The usual method of calibrating β (core resonance integral) from one of the observed transitions in the semi-empirical methods is critically examined with respect to the triplet levels of this molecule. Semi-empirical parameters are found to have a pronounced effect on the energy of the triplets and the triplet-triplet transitions; but the intensities of such transitions are quite insensitive to the choice of such parameters.Numerical results show several 3B1u → 3E2g transitions of various intensities. Out of these, the transitions which correspond energetically to the observed triplet-triplet bands are found to have low intensity. Some strong triplet-triplet bands are predicted in the far ultra violet region.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050303
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  • 173
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    Many-electron problems III scaling of the density distributions and the potential fields (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 311-317 
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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 Hellmann-Feynman theorem has been used to prove some energy relations. In this paper it is shown that in a scaled co-ordinate system both the charge density and the potential field of neutral atoms may be scaled so that the corresponding scaled quantities are independent of the atomic number. In the proof the momentum theorem of real functions is used.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050306
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    Correlation problems in atomic and molecular systems IIISee [1] for Parts I and II.. Rederivation of the coupled-pair many-electron theory using the traditional quantum chemical methodstSee [2].Part of this work was carried out at the Institute of Physical Chemistry, Czechoslovak Academy of Sciences, Prague, Czechoslovakia. (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 359-379 
    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 equations of the coupled-pair many-electron theory (CPMET) for the closed shell systems are rederived both in the spin-orbital and orbital forms without the use of second quantization, Wick's theorem or the technique of Feynman-like diagrams. Only the Slater rules are used for the calculation of necessary matrix elements. A comparison with earlier papers shows clearly the usefulness and conceptual simplicity of the mathematical methods of quantum field theory both in the derivation of the CPMET, in spin-orbital form, and in the process of excluding spin variables.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050402
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    Ab initio calculation of electronic states of the ions H4+ and H5+ (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 669-682 
    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: Electronic state calculations for the ions H4+ (with symmetries D4 and C2v) and H+5 (with symmetries D5 and D2d) are made using the valence-bond method. All the configurations obtained from the given set of 1s-functions of Slater type are taken into account. Space functions are used throughout the computation (“spin-free quantum chemistry”). Preliminary quasidiagonalization of the secular equation is implemented by the construction of the multiplet eigenfunctions 2S+1Γ(α) from the initial variational functions. The results of the calculations are as follows: the ion H+4 is unstable, the ion H+5 is stable with equilibrium nuclear conformation of symmetry D2d and with the energy of dissociation into H+3 and H2 near 4 eV.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050607
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  • 176
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    Masthead (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971) 
    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.560050401
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  • 177
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    The isotropic invariants of fifth-rank cartesian tensors (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 381-386 
    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 orthonormal set of irreducible fifth-rank tensors having the required permutation symmetry is constructed. Various problems not encountered in the analogous problem for tensors of ranks two, three, four and six are discussed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050403
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  • 178
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    Masthead (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971) 
    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.560050101
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  • 179
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    Time-dependent quantum theory II. Absorption of light by dimers: Quantum theory and classical analogy (1971)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 5 (1971), S. 35-65 
    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 theory of light absorption by a pair of neighboring absorbers is developed in the point dipole approximation for the circumstance where excited states decay only by radiative damping. Comparison with classical local field theories, in which the monomers are represented by constant, frequency-dependent complex polarizabilities, shows that these local field theories are valid for non-harmonic absorbers only in the weak interaction limit, and only when there exist no states with both monomers simultaneously excited (e.g. one excited vibrationally, the other electronically) that are nearly degenerate with the single excitation states and also connected to them by appreciable transition moments. Failure of the local field theories is, thus, shown to be a consequence of the non-harmonic nature of real absorbers.Using a general relation between the level-shift function and complex polarizability, a recipe is formulated for calculating the complex polarizability and spectrum of a dimer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560050104
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  • 180
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    Lamellar and interlamellar structure in melt-crystallized polyethylene. II. Lamellar spacing, interlamellar thickness, interlamellar density, and stacking disorder (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 85-114 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements of the small-angle scattering power and the degree of crystallinity in melt-crystallized high-density polyethylene have been used to evaluate the “amorphous” density in situ by the relation, \documentclass{article}\pagestyle{empty}\begin{document}$ (2\pi/V)\int_0^\infty {S\tilde g} (S)dS = (\rho_{\rm c} - \rho_{\rm a})^2 \upsilon_{{\rm er}} (1 - \upsilon_{{\rm er}}) $\end{document} where V is the irradiated volume and ḡ(S) is the “slit-smeared” absolute intensity. The amorphous density is a function of sample history and is always higher than the extrapolated melt density. After slit-height correction, and within the experimental error, the ratio of the two observed long periods is 2:1 at all temperatures (25--126°C). The lamellar thickness and the average interlamellar spacing are obtained from the degree of crystallinity and the first corrected long period. At increasing temperatures between 25°C and 110°C, the lamellae become thinner while the interlamellar zone expands by almost half. Over this range the changes are reversible with temperature. Above 110°C, both the lamellae and the interlamellar region expand with temperature. The thickening is partially reversible upon recooling. Other results obtained include measurements of stacking disorder and of microstructural changes with crystallization temperature and with time at ambient temperature.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090107
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  • 181
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    Planar organosilicon polymers (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 143-160 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Work on two sheet organosilicon polymers, one derived from the mineral chrysotile and the other from the mineral apophyllite, is described. This work provides direct evidence that both these polymers are composed of sheets. In addition, it shows that in the chrysotile-derived polymer the sheets curl into scrolls, and that in the apophyllite-derived polymer the sheets are essentially flat.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090110
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  • 182
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    Viscoelastic behavior of low molecular weight polystyrene (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 209-243 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The shear creep and creep recovery behavior of narrow molecular weight distribution polystyrene samples of low molecular weight, 1.1 × 103, 3.4 × 103, and 1.57 × 104 are reported as a function of temperature, near and above the glass temperature. Time-temperature equivalence for the total creep compliance is found to be nonapplicable, and in fact the steady-state recoverable compliance, Je, is a strong function of temperature. The time-scale shift factors for the recoverable compliance are analyzed in the light of free volume theory. Viscosity data are presented for samples with molecular weights between 1.1 × 103 and 6.0 × 105. The temperature dependence of the characteristic time constant ηJe can be explained in terms of free volume concepts whereas that of viscosity η cannot. Effects of residual molecular weight heterogeneity are demonstrated.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090202
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  • 183
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    Scattering of light by deformed three-dimensional spherulites (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 295-311 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A theoretical calculation of the Hv light-scattering patterns for deformed three-dimensional spherulites is presented. Affine deformation is assumed. The optic axis of the scattering element is allowed to lie at an arbitrary angle ß to the radius which is permitted to change in the course of the deformation in a manner that may depend upon the angular location in the spherulite. The consequences of twisting of the optic axis about the spherulite radius are also explored.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090206
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  • 184
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    Adsorption of polydimethylsiloxanes from solution on glass (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 331-343 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The adsorption of polydimethylsiloxane polymers from solution on glass has been studied. The amount of polymer adsorbed depends markedly on the solvent because of specific solvent - surface interactions. The presence of silanol groups in the polymer, particularly as endgroups, markedly increases the amount of polymer adsorbed. Large differences are shown between the adsorption of the commercially available, and fully trimethylsilylated polydimethylsiloxanes of narrow molecular weight distribut on. Possible adsorption mechanisms are discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090208
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  • 185
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    Composition equation for block copolymers (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 383-384 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090214
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  • 186
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    Long-chain branching in low-density polyethylene (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 421-430 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A method is given for the analysis of long-chain branching in polymers by using combined GPC and intrinsic viscosity measurements. A computer program was written to evaluate branching indices by a tabular, iterative method. The method was applied to the evaluation of long-chain branching in low-density polyethylene.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090303
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  • 187
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    Side-chain relaxation in stereoregular poly(isobutyl methacrylate) (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 431-435 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effects of stereoregularity on the low-temperature relaxation processes were studied by dynamic mechanical measurements on isotactic and syndiotactic polyisobutyl methacrylates (iso-PiBMA and syn-PiBMA). The α, β, and γ relaxation processes were observed in both stereoregular forms. Both the α, and β loss peaks were at lower temperatures for iso-PiBMA than for syn-PiBMA. The γ loss peak was observed at about -155°C at 30 Hz for both forms, and the apparent activation energy of this process was same for both samples within experimental error (6.7 ± 0.5 kcal/mole). It was reduced from these results that the α and β processes are both considerably influenced by the isotactic configuration but the γ process is not.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090304
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  • 188
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    Polyphenylenes (1971)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science: Macromolecular Reviews 5 (1971), S. 385-430 
    Details
    ISSN: 0076-2083
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.230050105
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  • 189
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    Stereochemistry of poly(vinyl alcohol) (1971)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science: Macromolecular Reviews 5 (1971), S. 431-540 
    Details
    ISSN: 0076-2083
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 41 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.230050106
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  • 190
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    Studies on formaldehyde condensation resins. XIII. Gelation of acetoguanamine-formaldehyde resin (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 15-26 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The gelation reaction of acetoguanamine with formaldehyde was investigated in the light of the gelation theory for tetrafunctional amino resins described in the previous paper. The gel time and extents of reaction of formaldehyde, amino groups, and imino groups varied with the molar ratio in the feed, but values of K (the ratio of the rate constant for condensation to that for addition) and k (the ratio of the rate constant for addition of the imino group to that of the amino group) were nearly constant. When the catalyst concentration was increased, the gel time, extents of reaction of each functional group, and the values of K and k varied; in particular K increased markedly. From the results of varying the molar ratio and concentration of acidic catalyst, it was found that the number of methylol groups per molecule of acetoguanamine at the gel point was influenced by the reaction conditions but the number of methylene linkages per molecular of acetoguanamine was nearly constant at about 0.6, regardless of reaction conditions. The number-average molecular weights up to the gel point varied with the reaction conditions, but at the gel point they were all nearly constant at about 385.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090102
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  • 191
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    Ultraviolet photoelectric effects in polyethylene (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 543-555 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Photocurrents developed in polyethylene in the wavelength range 360-180 nm have been measured. The action spectra show features which can be related to the corresponding features in the absorption spectrum, and in addition there is electron injection from the metal electrode at a wavelength determined by the electrode material. The time dependence of the response indicates that a long-lived space charge is formed in the material.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090312
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  • 192
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    Photocurrents in simple polymer systems. II (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 569-576 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Large photocurrents have been observed in films of some simple polymers (containing no π-orbitals), of which poly(vinyl fluoride) is a typical example. Not only are the currents large (up to 10-5 A/cm2) but also they are capable of being excited by light in the visible wavelength region where absorption by the polymer is too low to be detectable. The results indicate that the effects are electronic, rather than ionic, in nature.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090314
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  • 193
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    Some probability relations in multicomponent copolymers (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 577-584 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It was previously shown that for a stationary random copolymer of A, B, and C, we have in general p(AB) + p(AC) = p(BA) + p(CA), etc., in place of p(AB) = p(BA) which is valid for a stationary binary copolymer. Here, p(AB) for example, is the probability that a randomly picked pair of consecutive comonomers in the polymer consists of an A followed by a B. For a stationary ternary copolymer produced by a first-order Markovian addition mechanism, we show that PABPBCPCA/PACPCBPBA = k, where k is a constant characteristic of a particular set of three monomers but independent of its composition. Here, PAB is the conditional probability of finding a monomer of B given that its immediate predecessor is an A. We further show that if the individual rate constants of the monomer additions involved take a special form such as used in the Alfrey-Price Q-e scheme, then we have k = 1 irrespective of the kinds of monomers, and in addition we have p(AB) = p(BA), p(AC) = p(CA), etc. Thus, although these latter results were previously proposed by Ham as an alternative basis to supplant the Q-e scheme, they may rather be regarded as mathematical consequences of special assumptions adopted for the form of the individual rate constants. For a stationary random copolymer of four components A, B, C, and D, we have p(AB) + p(AC) + p(AD) = p(BA) + p(CA) + p(DA), etc., in general. For a first-order Markovian four-component copolymer, we show that there are seven different combinations of the conditional probabilities that are constants (k1, k2,…, k1) independent of the monomer composition. Again, if we assume the same special form for the rate constants involved, we find that all the seven constants k1, k2, …, k7 reduce to unity and p(XY) = p(YX) for X,Y, = A, B, C, D.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090401
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  • 194
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    Laser-Raman spectra of vinyl chloride-vinylidene chloride copolymers (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 717-729 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Several copolymers as well as homopolymers of vinylidene chloride and vinyl chloride have been examined by Raman spectroscopy. Probabilities of concentrations of monomer sequences have been calculated from known reactivity ratios. Surface scattering intensities at some frequencies were found to be linearly proportional to specific microstructure concentrations. Normalization of scattering intensities was accomplished using the intensity of the CH2 asymmetric stretching mode at 2926 cm-1, which is common to all samples examined. Good correlation was found for the concentrations of comonomer sequences {B}, {BB}, {BBB}, {AA} and {AAAA} in which A denotes vinylidene chloride and B vinyl chloride.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090411
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  • 195
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    Comments on “an analytical solution to tung's axial dispersion equation. Applications in gel permeation chromatography” (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 247-250 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070150121
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  • 196
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    Permeability of polyethylene film to organic vapors (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 327-339 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The permeabilities of polyethylene film to vapors of 19 organic compounds at temperatures of 21°C, 38°C, and 49°C were measured by a sorption method. The film was formed into a pouch, which was filled with silica gel, sealed, and suspended in a saturated atmosphere. The permeability was calculated from the steady-state rate of the gain in weight. The permeability data were correlated with the Hildebrand solubility parameters of the organic substances.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070150207
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  • 197
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    Flow of viscous fluid through a circular aperture (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 369-379 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The creeping flow of a highly viscous incompressible fluid through a circular aperture located in an infinitely wide horizontal plate is analyzed by solving Navier-Stokes equations without inertia terms. Solutions for vertical and radial velocities as well as pressure have been obtained in terms of integral equations with an undetermined Kernal function. This function has been evaluated by assuming several different velocity distributions at the aperture, and the corresponding pressure drop for each case has been calculated. The results show that the pressure loss for a given flow rate goes through a minimum as the assumed velocity profile changes from flat to parabolic. Based on the minimum energy dissipation theorem of Helmholtz, the most appropriate velocity distribution is discussed. Experimental data obtained using sharp-edged orifices are compared with theoretical predictions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070150210
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  • 198
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    Transport properties of eastman cellulose acetate membranes: Influence of diffusant size and shape on permeability (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 597-606 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Eastman cellulose acetate membranes (acetyl content = 40%) have been studied by means of dialysis rate experiments with uncharged permeants of selected sizes and shapes. The experimental results show that the high flux membranes exert no molecular size or shape selectivity on the transport of permeants whose molecular weights are less than 1152. The membranes used in desalination, however, are selective as to molecular size and shape. Desalination membranes, therefore, may be useful in separations where differences in size and shape are present.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070150308
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  • 199
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    The fracture toughness and stress corrosion cracking characteristics of an anhydride-hardened epoxy adhesive (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 641-659 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The toughness and stress corrosion cracking characteristics of an epoxy resin (DER 332) hardened with hexahydrophthalic anhydride (HHPA) were investigated. The epoxy was studied in both the bulk and bond form, and its properties were compared with an amine-hardened (tetraethylene pentamine, TEPA) system. The toughness, GIc, of the anhydride system varied less as a function of ratio of hardener-to-resin content and postcure temperature than it did in the TEPA-hardened system. Like the latter, however, its toughness in the bulk and bond forms could not be correlated, but GIc of the joints was dependent on tensile modulus and/or yield strength of the bulk epoxy. Both systems were also toughened in the vicinity of the crack tip by water for short-time loading, but their long-time load carrying capability was reduced by a water environment. The anhydride hardened system was more sensitive to strength loss in water than the amine system. The fracture morphology for the two systems was the same, i.e., fast cracking occurred cohesively near the center of the bond, and slow cracking occurred at the interface.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070150311
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  • 200
    Electronic Resource
    Electronic Resource
    Pyrolysis of treated rayon fiber (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 715-729 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The thermal decomposition behavior of rayon yarn which had been treated with various chlorosilanes and boron-phosphorus compounds was determined at temperatures up to 800°C. It was found that 70% of the available hydroxyl groups in rayon would react with dichlorodiphenylsilane and that the treated yarn had an initial decomposition temperature 125°C higher than that of untreated rayon. The weight loss of the treated yarn at 800°C was dependent on the nature of the chlorosilane and the type of posttreatment used. Alkylchlorosilanes produced higher weight losses than did the arylchlorosilane-treated rayons. Treatment of rayon yarn with bis(chlorodiphenyl-phosphine)decaborane (BCDPD) or dimeric chlorophospha(III)-o-carborane (DCPC) resulted in an increase in the char yield of the pyrolyzed yarns. In the case of untreated rayon, weight retention at 800°C was 20%, whereas the treated yarns yielded boronated residues of 42-53%. Carbon yields as high as 28% were obtained with the BCDPD treatment. This treatment also resulted in substantial improvement in the oxidative stability of rayon at temperatures up to 250°C.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070150316
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