title: Elimination of Translational and Rotational Motions in Nuclear Orbital Plus Molecular Orbital Theory:  Contribution of the First-Order Rovibration Coupling.
abstract: The translation- and rotation-free nuclear orbital plus molecular orbital (TRF-NOMO) theory was developed to determine nonadiabatic nuclear and electronic wave functions. This study implemented a computational program for the TRF-NOMO method including first-order rotational terms, which corresponds to rovibronic coupling. Numerical assessments of first-order TRF-NOMO Hartree-Fock as well as second-order Møller-Plesset perturbation methods were carried out for several small molecules. The first-order contributions give small corrections in energy. Thus, we confirm that the approximate zeroth-order treatment is sufficient for eliminating the rotational contamination.
authors.affiliation: Department of Chemistry, School of Science and Engineering, Waseda University, Tokyo 169-8555, Japan.
authors.forename: Kaito
authors.initials: K
authors.lastname: Miyamoto
authors.affiliation: Department of Chemistry, School of Science and Engineering, Waseda University, Tokyo 169-8555, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Hoshino
authors.affiliation: Department of Chemistry, School of Science and Engineering, Waseda University, Tokyo 169-8555, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Nakai