Efficient implementation of the Hiller--Sucher--Feinberg identity for the accurate determination of the electron density

Journal Article · Sat Jan 01 04:00:00 EST 1994 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.466961· OSTI ID:5429131

Challacombe, M; Cioslowski, J ^[1]

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1. Department of Chemistry and the Supercomputer Computations Research Institute, Florida State University, Tallahassee, Florida 32306-3006 (United States)

A new, highly optimized implementation of the Hiller--Sucher--Feinberg (HSF) identity is presented. The HSF identity, when applied to molecular wave functions calculated with Gaussian-type basis functions, not only improves the overall accuracy of the electron density by more than an order of magnitude, but also yields approximate cusps at nuclei. The three classes of molecular integrals, L, U, and V, which are encountered in the calculation of the HSF density, are derived in compact form. Efficient algorithms for the accurate evaluation of these integrals are detailed, including a novel approach to the necessary numerical quadratures and the thresholding of two-electron V integrals. Hartree--Fock (HF) electron densities calculated with both the conventional definition and from the HSF identity are compared to their respective HF limits for a variety of diatomic molecules and basis sets. The average error in the calculated HSF electron densities at non-hydrogen nuclei equals 0.17%, which constitutes a marked improvement over an error of 5.77% in the conventional densities.

• DOE Contract Number: FC05-85ER25000
• OSTI ID: 5429131
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 100:1; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

664100* -- Theory of Electronic Structure of Atoms & Molecules-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ACCURACY
ALGORITHMS
CALCULATION METHODS
ELECTRON DENSITY
FUNCTIONS
GAUSS FUNCTION
HARTREE-FOCK METHOD
INTEGRALS
MATHEMATICAL LOGIC
OPTIMIZATION
WAVE FUNCTIONS