Influence of relativistic valence-core correlation on p-state fine structure in some univalent systems

Abstract

Single-configuration relativistic Hartree–Fock values of fine-structure separations are calculated for p-levels in systems with a single electron outside a closed-shell core, both with and without allowance for relaxation and polarization of the core. Effects of the polarization of the atomic core by the valence electron are included by the addition of a polarization potential to the one-electron Hamiltonian. The results obtained generally compare well with available experimental data and indicate a significant influence of core polarization on fine-structure splittings. Contributions of the relaxation of the core are considerable only for the heavier systems. The choice of the cut-off parameter r0 in the polarization potential, as well as of the shape of the cut-off function, and the success of the ab initio approach are discussed. It is suggested that for indium and thallium, in contrast to the case for rubidium, silver, and gold, the simplified picture of a core plus a single valence electron is no longer entirely satisfactory.