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Title: Asymptotic expansion of two-electron integrals and its application to Coulomb and exchange lattice sums in metallic, semimetallic, and nonmetallic crystals

Journal Article · · Journal of Chemical Physics
DOI:https://doi.org/10.1063/1.4828796· OSTI ID:22251480
;  [1];  [1]
  1. Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801 (United States)

A simple, easily implemented, accurate, and efficient approximation of long-range electron-electron-repulsion and electron-nucleus-attraction integrals is proposed. It replaces each product of two atomic-orbital (AO) basis functions of an electron by a point charge centered at the midpoint of the two AO's. The magnitude of the point charge is equal to the overlap integral of the two AO's. Each integral is then rapidly evaluated in the direct algorithm as a Coulomb interaction between two point charges. This scheme is implemented in ab initio Hartree–Fock crystalline orbital theory and tested for one-, two-, and three-dimensional solids of metallic, semimetallic, and nonmetallic electronic structures, in which the lattice sums of the direct Coulomb and/or exchange interactions are expected to be slowly convergent. It is shown that this approximation reduces operation and/or memory costs by up to an order of magnitude to achieve converged lattice sums, although the scaling (size dependence) of operation cost is unchanged. An improved criterion for truncating the exchange lattice sum is also proposed.

OSTI ID:
22251480
Journal Information:
Journal of Chemical Physics, Vol. 139, Issue 18; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
Country of Publication:
United States
Language:
English