Indentities Relating Spin-Spin and Orbit-Orbit to Spin-Orbit Interactions

Abstract

We derive indentities that express spin-spin and orbit-orbit interactions in terms of two-electron spin-orbit matrix elements. They can reduce, in effect, any study of the two-electron Breit-Pauli Hamiltonian for atoms or molecules to one of determining the spin-orbit integrals, thereby considerably unifying and simplifying the whole analysis.