On the origin of the heavy atom effect in the fine-structure splitting of the 1 2Π state of alkali metal P2-rare gas van der Waals molecules

Abstract

The fine-structure splitting of the (1 2ΠΩ,ν) levels in Li(1s 22p,2P)Ar and Li(1s 22p,2P)Ne is determined. Analysis of the electronic wave functions demonstrates that the heavy atom contribution to the fine-structure splitting results from the antibonding mixture of valence pπ orbitals on the rare gas and metal atoms. Rydberg orbitals do not contribute significantly to the heavy atom effect.