Residual limitations of theoretical atomic-electron binding energies

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Abstract
Relativistic calculations of atomic-electron binding energies have been refined by using the relativistic LS-average scheme to treat open outer shells, by including self-energy corrections for shells up to 3p as well as 4s, and accounting for energy shifts caused by interaction with Coster-Kronig continua. The contributions of ground-state correlation were estimated from the pair energy calculated through nonrelativistic many-body theory. The need for a relativistic theory of correlations is noted. As in our previous work, the calculations include relaxation, the effect of finite nuclear size, Breit interaction, and quantum-electrodynamic (QED) corrections. Results are compared with binding energies measured on free atoms and with solid-phase measurements on metals that have been corrected for solid-state shifts; these shifts were calculated under the assumption of complete screening with the core-ionized site treated as a neutralized metallic impurity atom in the original metallic host. Discrepancies between experimental energies and relativistic independent-particle calculations including relaxation, QED, and finite-nuclear-size corrections are traced to correlation corrections, uncertainties in the self-energy, and neglect of the effect of (super-)Coster-Kronig fluctuations.