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Variational estimates for exchange‐correlation interaction obtained within Super‐CI approach to MCSCF approximation
Author(s) -
Gusarov S. I.,
Goidenko I. A.,
Dmitriev Yu. Yu.,
Labzowsky L. N.
Publication year - 2007
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.21431
Subject(s) - degenerate energy levels , formalism (music) , feynman diagram , physics , configuration interaction , quantum mechanics , wave function , perturbation theory (quantum mechanics) , electronic structure , statistical physics , mathematical physics , molecule , art , musical , visual arts
Two possible variation approximations for the exchange‐correlation interaction are considered in the one‐particle approach to the electronic structure theories. These approximations appear within the Super‐CI procedure in the MCSCF optimization schemes. The basic formalism shows its close connection to the Green's function theory in the extended Koopmans' approach. An immediate implementation of the corresponding Super‐CI Green's functions is the Møller‐Plesset open‐shell and quasi‐degenerate perturbation expansions, and the density matrix functional theory. The relativistic formulation which is based on the relativistic extended Koopmans' approach can be used to calculate radiation corrections in frames of the conventional Feynman formalism. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007