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  • 1
    Electronic Resource
    Electronic Resource
    Hartree-like methods in electronic structure theory (1978)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 13 (1978), S. 189-198 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We consider the “Hartree Problem,” here defined as the problem of finding the orthogonal one-electron states which in a single determinant minimize the electronic energy, excluding exchange contributions. These states may provide a useful basis for correlation-energy studies. It is shown how the “Hartree Problem,” although superficially not of pseudoeigenvalue form, can nevertheless be cast in such a form and solved by an iterative diagonalization process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560130204
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  • 2
    Electronic Resource
    Electronic Resource
    Evaluation of GTO molecular integrals (1983)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 23 (1983), S. 1469-1478 
    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: Methods for evaluating the function Fm(t) occurring in molecular integrals over Gaussian-type orbitals are reviewed and extended. Formulas based on Bessel function and continued-fraction expansions are analyzed. The recommended evaluation procedures, embodied in a portable computer program, involve Padé approximations for various argument intervals and use recursion in m. The program is economical in storage requirements and faster than those in current use.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560230429
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  • 3
    Electronic Resource
    Electronic Resource
    Evaluation of computational aspects of a modified CS-LCAO-SCF-CO strategy for electronic structure calculations of extended model chains (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 141-152 
    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 analysis is made of the mathematical and computational implications of a recently proposed scheme to calculate the electronic structure of chainlike systems without explicit use of the LCAO density matrix elements. The infinite chain of hydrogen atoms is chosen as a simple test case illustrating the underlying difficulties associated with the scheme. It turns out that the positive features that have motivated the development of this approach do not balance the numerical difficulties. It seems unlikely that, in routine applications, the new strategy will become a real competitor to the existing programs.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260817
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  • 4
    Electronic Resource
    Electronic Resource
    An alternative computational strategy for direct space hartree-fock calculations on extended model chains (1985)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 27 (1985), S. 219-229 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Based on previous analyses of slowly convergent exchange lattice sums entering the configuration space restricted Hartree-Fock-Roothaan scheme for chain systems, an alternative computational strategy is developed. Within the present formalism, the traditionally used finite Fourier transform of k-dependent LCAO density matrices are by-passed and an advantageous computational organization is obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560270212
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  • 5
    Electronic Resource
    Electronic Resource
    Improved correlation energy functional (1996)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 59 (1996), S. 3-6 
    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: Irregularities in the connection of the high- and low-density forms of the Perdew-Zunger correlation energy functional lead to computational difficulties that are removed by a new parametrization. These parametrizations and a number of other correlation functionals are compared and discussed. © 1996 John Wiley & Sons, Inc.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Accurate calculation of Fourier transform of two-center Slater orbital productsSupported in part by the National Science Foundation (Grant GP-11170) and by the Air Force Office of Scientific Research, Office of Aerospace Research, USAF, under Grant No. AFOSR-7 1-1992. The United States Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation hereon. (1972)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 601-607 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is presented which leads to accurate Fourier transform values of any 1s-1s Slater-type orbital overlap distribution. The numerical merits are discussed and illustrated by some examples.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560060402
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  • 7
    Electronic Resource
    Electronic Resource
    A note on the number of spanning trees in buckminsterfullerene (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 52 (1994), S. 525-528 
    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 “pedestrian” approach is used to enumerate the spanning trees in buckminsterfullerene. The approach is called “pedestrian” because calculations were carried out by hand and pocket calculator. The number of spanning trees obtained for buckminsterfullerene is 375,291,866,372,898,816,000, a number identical to the value reported by Brown et al. [J. Comput. Chem. 12, 1118 (1991)] who used a computationally more involved approach. © 1994 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560520846
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  • 8
    Electronic Resource
    Electronic Resource
    Critical study of plane-wave density-functional methods for extended systems (1995)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 56 (1995), S. 235-239 
    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: Calculations on simple systems can be used to study the convergence rates of plane-wave expansions in density-functional methods, to confirm their correctness and numerical stability, and to assess their sensitivity to choice of exchange-correlation functionals and pseudopotentials. This initial communication compares three sets of results on a crystal of noninteracting hydrogen atoms: those obtained from a code we developed for the purpose of making such studies; those generated from the CASTEP code (distributed by Molecular Simulations, Inc.); and those from the PLANE_WAVE code (distributed by Biosym Technologies, Inc.). © 1995 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560560825
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  • 9
    Electronic Resource
    Electronic Resource
    Light cone hamiltonian in quantum chemistry: Gaussian basis representation for quantum electrodynamics (1995)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 56 (1995), S. 277-282 
    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 rational, closed-form Hamiltonian formulation of quantum electrodynamics is presented in a Gaussian basis representation, obtained using a discretized light-cone field quantization method. This approach illustrates the possibility that traditional methods of quantum chemistry may become applicable for the nonperturbative treatment of problems currently accessible only perturbatively if at all, as for example relativistic many-electron interactions in atoms and molecules. © 1995 John Wiley & Sons, Inc.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560560830
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  • 10
    Electronic Resource
    Electronic Resource
    Sinc collocation in quantum chemistry: Solving the planar coulomb Schrödinger equation (1996)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 60 (1996), S. 1311-1318 
    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: Dirac bra-ket notation is introduced for the Whittaker cardinal (Sinc) functions and a previously unreported completeness relation for these quantities is presented and derived. With the use of this completeness relation it becomes simple to transform to a Sinc-basis the eigenvalue equations arising from a light-cone quantization of field theory or the similar equations occurring in nonrelativistic quantum mechanics. The simplicity and power of Sinc-function expansions is illustrated by computation of the eigenvalues and eigenfunctions of the position-space planar Coulomb equation, a problem for which convergence has not been achieved by a variety of other computational methods. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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