A multireference many-body perturbation theory study of Be + H2 → BeH2

Abstract

A multireference many-body perturbation theory (MR-MBPT) is discussed and illustrated by the model problem of the vertical insertion pathways of Be into H2. The results are compared with full CI and previous coupled-cluster results. The comparison of MR-MBPT results reveals good qualitative agreement. It is suggested that a more extensive reference space is necessary even for this small problem in order to achieve quantitative results. The paper discusses the question of orbital choice in MR-MBPT methods.