The relation between satellite peaks in x-ray emission and x-ray photoemission spectra

A unified model is given to explain the satellite structures observed in x-ray emission spectroscopy (XES) and x-ray photoelectron spectroscopy (XPS) and the relationships between the two. This model accounts for electron correlation by the use of configuration interaction, rather than the heuristic ’’shake-up’’ approach, and actual eigenstates of the system are considered. Two situations are discussed, differing in whether the final XES states have holes in core or valence shells. For core-to-core XES transitions, the correlation-state structure is almost identical in initial and final states. Large satellite intensities may be observed in XPS, but not in XES, in accord with experiment. In core-to-valence XES transitions, the satellite structure should be similar to that observed in XPS, as observed. Detailed CI calculations for the 3s spectra of Ar are compared with measured spectra.