Effects of core-level degeneracies on core-level spectra
Effects of core-level degeneracies on X-ray photoemission spectra are considered theoretically and computationally. Processes within each degenerate sub-level manifold are treated by a leading-order cumulant approximation, and processes which connect spin-orbit or crystal-field split levels to leading order in the core-electron self-energy. The cumulant approximation is consistent with earlier asy