title: Multireference perturbation theory with optimized partitioning. II. Applications to molecular systems.
abstract: The second-order multireference perturbation theory using an optimized partitioning, denoted as MROPT(2), is applied to calculations of various molecular properties-excitation energies, spectroscopic parameters, and potential energy curves-for five molecules: ethylene, butadiene, benzene, N(2), and O(2). The calculated results are compared with those obtained with second- and third-order multireference perturbation theory using the traditional partitioning techniques. We also give results from computations using the multireference configuration interaction (MRCI) method. The presented results show very close resemblance between the new method and MRCI with renormalized Davidson correction. The accuracy of the new method is good and is comparable to that of second-order multireference perturbation theory using Møller-Plesset partitioning.
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan. cedziu@qcl.t.u-tokyo.ac.jp
authors.forename: Henryk A
authors.initials: HA
authors.lastname: Witek
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Nakano
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Hirao