Density fitting for three-electron integrals in explicitly correlated electronic structure theory

James C. Womack*, Frederick R. Manby

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

10 Citations (Scopus)
14 Downloads (Pure)

Abstract

The principal challenge in using explicitly correlated wavefunctions for molecules is the evaluation of nonfactorizable integrals over the coordinates of three or more electrons. Immense progress was made in tackling this problem through the introduction of a single-particle resolution of the identity. Decompositions of sufficient accuracy can be achieved, but only with large auxiliary basis sets. Density fitting is an alternative integral approximation scheme, which has proven to be very reliable for two-electron integrals. Here, we extend density fitting to the treatment of all three-electron integrals that appear at the MP2-F12/3*A level of theory. We demonstrate that the convergence of energies with respect to auxiliary basis size is much more rapid with density fitting than with the traditional resolution-of-the-identity approach. (C) 2014 AIP Publishing LLC.

Original languageEnglish
Article number044118
Number of pages12
JournalJournal of Chemical Physics
Volume140
Issue number4
DOIs
Publication statusPublished - 28 Jan 2014

Keywords

  • AUXILIARY BASIS-SETS
  • 2-ELECTRON GAUSSIAN INTEGRALS
  • WAVE-FUNCTIONS
  • CORRELATION ENERGIES
  • PERTURBATION-THEORY
  • RI-CC2 CALCULATIONS
  • CONVERGENCE
  • COMPUTATION
  • RI-MP2
  • TERMS

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