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 JAMP  Vol.6 No.6 , June 2018
Extended Koopmans’ Approximation for CASDFT Exchange-Correlation Functional
Abstract:
A new density functional theory approach based on a complete active space self-consistent field (CASSCF) reference function in Extended Koopmans’ approximation is discussed. Recently, the number of generalizations of density functional theory based on a multiconfigurational CASSCF reference function with exact exchange (CASDFT) was introduced. It was shown by one of the authors (Dr. Gusarov) that such a theory could be formulated by introducing a special form of exchange-correlation potential. To take into account an active space and to avoid double counting of correlation energy the dependence from on-top pair density P2(r) as a new variable was introduced. Unfortunately, this requires a deep review and reparametrization of existing functional expressions which lead to additional computational difficulties. The presented approach does not require introducing additional variables (like on-top pair density, P2(r)) and is based on Extended Koopmans’ theorem (EKT) approximation for multiconfigurational wave function within CASSCF method.
Cite this paper: Gusarov, S. and Dmitriev, Y. (2018) Extended Koopmans’ Approximation for CASDFT Exchange-Correlation Functional. Journal of Applied Mathematics and Physics, 6, 1242-1246. doi: 10.4236/jamp.2018.66104.
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