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Author Cioslowski, J. ♦ Stefanov, B. B. ♦ Tan, A. ♦ Umrigar, C. J.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PHYSICS ♦ ISOELECTRONIC ATOMS ♦ ELECTRONIC STRUCTURE ♦ BERYLLIUM IONS ♦ COMPUTER CALCULATIONS ♦ ELECTRON CORRELATION ♦ ELECTRON DENSITY ♦ HARTREE-FOCK METHOD ♦ HELIUM ♦ HYDROGEN IONS 1 MINUS ♦ LITHIUM IONS ♦ MULTICHARGED IONS ♦ QUANTUM MECHANICS
Abstract Identities for the electron intracule density {ital I}({bold R}) in atoms and molecules are derived within the Hiller--Sucher--Feinberg (HSF) formalism. It is proven that, when applied to arbitrary (exact or approximate) electronic wave functions, these identities produce intracule densities that satisfy a modified condition for the electron coalescence cusp. A corollary of this proof provides a new, simplified derivation of the cusp condition for the exact {ital I}({bold R}). An expression for the Hartree--Fock approximation to the HSF electron intracule density that contains only two- and three-electron terms is obtained and its properties are analyzed. A simple scaling of the three-electron contributions in this expression assures integrability of the approximate {ital I}({bold R}) and improves its overall accuracy. Numerical tests carried out for the H{sup {minus}}, He, Li{sup +}, Be{sup 2+}, Li, and Be systems demonstrate that the application of the scaled HSF-type identity to Hartree--Fock wave functions affords dramatic improvements in the short-range behavior of the electron intracule density. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.
ISSN 00219606
Educational Use Research
Learning Resource Type Article
Publisher Date 1995-10-08
Publisher Place United States
Journal Journal of Chemical Physics
Volume Number 103
Issue Number 14


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