Generalization of the optimized-effective-potential model to include electron correlation: A variational derivation of the Sham-Schlueter equation for the exact exchange-correlation potential

Journal Article · Wed Mar 01 00:00:00 EST 1995 · Physical Review A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.51.2005· OSTI ID:6589992

Casida, M E ^[1]

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1. Departement de Chimie, Universite de Montreal, Case Postale 6128, Succursale Centre-ville, Montreal, Quebec, H3C 3J7 (Canada)

The now classic optimized-effective-potential (OEP) approach of Sharp and Horton [Phys Rev. 90, 317 (1953)] and Talman and Shadwick [Phys. Rev. A 14, 36 (1976)] seeks the local potential that is variationally optimized to best approximate the Hartree-Fock exchange operator. The resulting OEP can be identified as the exchange potential of Kohn-Sham density-functional theory. The present work generalizes this OEP approach to treat the correlated case, and shows that the Kohn-Sham exchange-correlation potential is the variationally best local approximation to the exchange-correlation self-energy. This provides a variational derivation of the equation for the exact exchange-correlation potential that was derived by Sham and Schlueter using a density condition. Implications for an approximate physical interpretation of the Kohn-Sham orbitals are discussesd. A correlated generalization of the Sharp-Horton--Krieger-Li-Iafrate [Phys Lett. A 146, 256 (1990)] approximation of the exchange potential is introduced in the quasiparticle limit.

• OSTI ID: 6589992
• Journal Information: Physical Review A; (United States), Vol. 51:3; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
ELECTRONIC STRUCTURE
ELECTRON CORRELATION
GREEN FUNCTION
QUASI PARTICLES
SELF-ENERGY
SPIN EXCHANGE
VARIATIONAL METHODS
CALCULATION METHODS
CORRELATIONS
ENERGY
FUNCTIONS
661100* - Classical & Quantum Mechanics- (1992-)
664100 - Theory of Electronic Structure of Atoms & Molecules- (1992-)