title: Efficient configuration selection scheme for vibrational second-order perturbation theory.
abstract: A fast algorithm of vibrational second-order Moller-Plesset perturbation theory is proposed, enabling a substantial reduction in the number of vibrational self-consistent-field (VSCF) configurations that need to be summed in the calculations. Important configurations are identified a priori by assuming that a reference VSCF wave function is approximated well by harmonic oscillator wave functions and that fifth- and higher-order anharmonicities are negligible. The proposed scheme has reduced the number of VSCF configurations by more than 100 times for formaldehyde, ethylene, and furazan with an error in computed frequencies being not more than a few cm(-1).
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Yagi
authors.forename: So
authors.initials: S
authors.lastname: Hirata
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Hirao