Communication: Second-order multireference perturbation theory with explicit correlation: CASPT2-F12

Toru Shiozaki*, Hans Joachim Werner

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

98 Scopus citations


An explicitly correlated complete active space second-order perturbation (CASPT2-F12) method is presented which strongly accelerates the convergence of CASPT2 energies and properties with respect to the basis set size. A Slater-type geminal function is employed as a correlation factor to represent the electron-electron cusp of the wave function. The explicitly correlated terms in the wave function are internally contracted. The required density matrix elements and coupling coefficients are the same as in conventional CASPT2, and the additional computational effort for the F12 correction is small. The CASPT2-F12 method is applied to the singlet-triplet splitting of methylene, the dissociation energy of ozone, and low-lying excited states of pyrrole.

Original languageEnglish (US)
Article number141103
JournalJournal of Chemical Physics
Issue number14
StatePublished - Oct 14 2010

ASJC Scopus subject areas

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


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