Electric Dipole Moment of Diatomic Molecules by Configuration Interaction. V. Two States of 2Σ+ Symmetry in CN

Abstract

In previous papers we developed techniques for the accurate calculation of dipole moments using moderate-sized (200 configuration) CI calculations. In this paper we consider the modifications necessary to treat higher excited states of a symmetry. It is shown that states below the state of interest must be considered simultaneously to a similar degree of accuracy. Calculations were performed on the 2Σ+ states of CN. For the X 2Σ+ state the SCF, CI, and experimental dipole moments (in debye) are 2.301, 1.465, and 1.45±0.08; for B 2Σ+ the CI and experimental values are −0.958 and −1.15±0.08. Spin hyperfine constants, and in particular spin density at the nucleus, are considered in the context of one-electron operator properties which may be calculated by the same methods used for the dipole moment. SCF and CI values for the spin density are compared with experimental values for several diatomic molecules.