Electron intracule densities with correct electron coalescence cusps from Hiller--Sucher--Feinberg-type identities

Journal Article · Sun Oct 08 04:00:00 EDT 1995 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.470437· OSTI ID:249408

Cioslowski, J; Stefanov, B B; Tan, A ^[1]; Umrigar, C J ^[2]

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1. Department of Chemistry and Supercomputer Computations Research Institute, Florida State University, Tallahassee, Florida 32306-3006 (United States)
2. Theory Center and Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853 (United States)

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}.

• OSTI ID: 249408
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 14 Vol. 103; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BERYLLIUM IONS
COMPUTER CALCULATIONS
ELECTRON CORRELATION
ELECTRON DENSITY
ELECTRONIC STRUCTURE
HARTREE-FOCK METHOD
HELIUM
HYDROGEN IONS 1 MINUS
ISOELECTRONIC ATOMS
LITHIUM IONS
MULTICHARGED IONS
QUANTUM MECHANICS