Ab initio computation of spin-orbit coupling constants in diatomic molecules

Abstract

Use of the Dirac equation leads to an expression for the spin-orbit coupling constant which involves both one and two-electron integrals, the former being due to nuclear charge and the latter providing screening of this charge. In this work both types of molecular integrals are considered and expanded into atomic integrals.Application to diatomic hydrides produces results which are in excellent agreement with experiment for molecules including a first row atom, and further demonstrates that the two-electron two centre integrals are very small. Calculations on non-hydrides indicate that this is not always the case.