Fast electron correlation methods for molecular clusters without basis set superposition errors

Muneaki Kamiya, So Hirata, Marat Valiev

Research output: Contribution to journalArticle


Two critical extensions to our fast, accurate, and easy-to-implement binary or ternary interaction method for weakly interacting molecular clusters [S. Hirata, Mol. Phys. 103, 2255 (2005)] have been proposed, implemented, and applied to water hexamers, hydrogen fluoride chains and rings, and neutral and zwitterionic glycine-water clusters with an excellent initial performance assessment result. Our original method included up to two- or three-body Coulomb, exchange, and correlation energies exactly and higher-order Coulomb energies in the dipole-dipole interaction approximation. In this work, the dipole moments are replaced by atom-centered point charges determined so that they reproduce the electrostatic potentials of the cluster subunits accurately and also self-consistently with one another in the cluster environment. They have been shown to lead to a dramatic improvement in the description of short-range electrostatic potentials not only of large, charge-separated subunits such as zwitterionic glycine but also of small subunits. Furthermore, basis set superposition errors (BSSEs) have been eliminated by combining the Valiron-Mayer function counterpoise (VMFC) correction with our binary or ternary interaction method. A new BSSE-correction scheme has been proposed on this basis, wherein three-body and all higher-order Coulomb effects on BSSE are also estimated. The BSSE-corrected ternary interaction method with atom-centered point charges reproduces the VMFC-corrected results within 0.1 kcalmol. The proposed method is not only more efficient but also significantly more accurate than conventional correlation methods uncorrected of BSSE.

Original languageEnglish (US)
Article number074103
JournalJournal of Chemical Physics
Issue number7
StatePublished - Mar 3 2008
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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