Relativistic self-consistent-field calculations of spin–orbit splittings in diatomic hydrides

Abstract

Spin–orbit splittings in a few diatomic hydrides are calculated as the differences between total energies of two Ω states of 2Π by the relativistic self-consistent-field method using Slater type functions as basis functions. The dependence of the spin–orbit splittings on the size and quality of basis sets is investigated and an optimal strategy for the selection of the basis set in the all-electron relativistic self-consistent-field calculation is suggested.Dipole moments are also calculated for the hydrides and the effects of the relativity and the spin–orbit coupling on dipole moments are discussed. The variation of the spin–orbit splittings with internuclear distances is investigated for the OH molecule. The present method is capable of yielding proper basis set limits and the calculations with a basis set of moderate size yield qualitatively good results although the Breit interaction term is omitted. The effects of the Breit term on the spin–orbit splittings are estimated to be considerably less than those of two-electron spin–orbit interaction terms.