Electric Dipole Moment of Diatomic Molecules by Configuration Interaction. I. Closed-Shell Molecules

Abstract

A scheme has been developed for selecting a manageable number of configurations (less than 200) to be used in a configuration interaction calculation to obtain the electric dipole moments of closed-shell diatomic molecules. Calculations have been performed on LiH (Re = 3.015 a.u.), CO (Re = 2.132 a.u. and R = 2.2853 a.u.), CS (Re = 2.89964 a.u.), and NaLi (R = 5.5 a.u.). A dramatic improvement over the restricted Hartree–Fock value is obtained. At Re the RHF, CI, and experimental dipole moments (in debye) are LiH: 6.00, 5.86, 5.83; CO: − 0.27, 0.12, 0.11; and CS: 1.56, 2.03, 1.97.