Widths of atomicM-shell vacancy states and quasiatomic aspects of radiationless transitions in solids

Widths of $M$-level vacancy states in atoms with $29\le Z\le 48$ have been measured by x-ray photoelectron spectroscopy. The results are consistently smaller, sometimes by a factor of ≥3, than expected from previous theory, and do not show the pronounced effect of predicted "super-Coster-Kronig" transitions. The Cu and Zn $L_3-M_{4,5}{M}_{4,5}$ Auger and $M_{4,5}$ photoelectron spectra have been measured; the Auger spectra exhibit characteristics of free-atom spectra and do not reflect the structure of the band from which the $M$ electrons originate. Drawing upon this and other evidence suggesting that atoms in solids can behave as quasifree when undergoing radiationless transitions, free-atom $M$ Auger and Coster-Kronig energies have been computed. These are smaller than measured energies because the effect of extra-atomic relaxation is absent. $M$-level widths were calculated with these energies, in a neutral-atom potential. Good agreement with experiment is attained.