Optimization of orbital-specific virtuals in local Moller-Plesset perturbation theory

Yuki Kurashige*, Jun Yang, Garnet K. -L. Chan, Frederick R. Manby

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

41 Citations (Scopus)

Abstract

We present an orbital-optimized version of our orbital-specific-virtuals second-order Moller-Plesset perturbation theory (OSV-MP2). The OSV model is a local correlation ansatz with a small basis of virtual functions for each occupied orbital. It is related to the Pulay-Saebo approach, in which domains of virtual orbitals are drawn from a single set of projected atomic orbitals; but here the virtual functions associated with a particular occupied orbital are specifically tailored to the correlation effects in which that orbital participates. In this study, the shapes of the OSVs are optimized simultaneously with the OSV-MP2 amplitudes by minimizing the Hylleraas functional or approximations to it. It is found that optimized OSVs are considerably more accurate than the OSVs obtained through singular value decomposition of diagonal blocks of MP2 amplitudes, as used in our earlier work. Orbital-optimized OSV-MP2 recovers smooth potential energy surfaces regardless of the number of virtuals. Full optimization is still computationally demanding, but orbital optimization in a diagonal or Kapuy-type MP2 approximation provides an attractive scheme for determining accurate OSVs. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3696962]

Original languageEnglish
Article number124106
Number of pages7
JournalJournal of Chemical Physics
Volume136
Issue number12
DOIs
Publication statusPublished - 28 Mar 2012

Keywords

  • perturbation theory
  • TRIPLES CORRECTION T
  • singular value decomposition
  • atomic structure
  • potential energy surfaces
  • electron correlations
  • MP2
  • COUPLED-CLUSTER THEORY
  • ELECTRON CORRELATION METHODS

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