THEORETICAL STUDIES OF SPIN COUPLING IN DIATOMIC MOLECULES

Abstract

The spin-spin, spin-orbit, and spin-other-orbit interaction constants have been determined for a variety of homonuclear and heteronuclear diatomic molecules using all-electron, ab initio methods. Both basis-set refinement and configuration interaction (CI) studies have been used to investigate the effect of wave-function accuracy on the coupling parameters and to determine the significance of various types of $\sigma$- and $\pi$-valence excitations. The effect of including correlation energy in the wave function is not straightforward; each electronic state must be examined with great care. Comparisons of our results will be made with experimental data and other published calculations.