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Comparison of Hartree-Fock and Kohn-Sham determinants as wave functions

โœ Scribed by Bou?, Petr

Publisher
John Wiley and Sons
Year
2000
Tongue
English
Weight
195 KB
Volume
21
Category
Article
ISSN
0192-8651

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โœฆ Synopsis

Kohn-Sham (KS)

and Hartree-Fock (HF) determinants were used as the true many-body wave functions for calculations of molecular energies, vibrational frequencies, and excited electronic states. The results justified common practice, encountered in the sum over states theories, in which these two determinants are used as the first-order approximation of the wave function. However, a distinct behavior with respect to the second-order perturbation calculation was observed for the two cases. The Raleigh-Schrรถdinger perturbation theory, which is formally identical to the Levy-Gรถrling formalism and analogous to the usual HF/Mรธller-Plesset approach, leads to rather discouraging results for the KS determinant. On the other hand, the rigid KS orbitals are more suitable for modeling of excited electronic states, which was indicated by the obtained transition energies for model molecules.

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