Shake-up satellite structure of transition metal auger spectra: L 2,3M 4,5M 4,5 spectra of the 4d metals

Abstract

Core hole Auger spectra of transition and noble metals have been relatively little studied because they are usually very broad, and because they provide little direct valence band information. Narrow and simple L 2,3M 4,5M 4,5 spectra of the 4d metals have been recently reported, however. Study of spectral peak energies has produced considerable information regarding ground and excited state electronic structure of these metals. Comparison of the spectra with atomic theoretical ones indicates that, whereas the L 2,3M 4,5M 4,5 spectra of In, Sn and Sb manifest atomic nature, in such open shell metals as Ag and Pd, these spectra evince intrinsic satellite structures below those of the Auger transitions proper. The L 2 and L 3 satellites, in contrast to those of the 3d LMM spectra, have the same form (within experimental error) and do not seem to involve L 2L 3X Coster-Kronig transitions, most of which are energetically forbidden. On the basis of the experimental systematics of the 4d spectra and the interpretation of 3d LMM spectra, we have identified these satellites as arising from shake-up involving spectator valence band holes. To our knowledge, such shake-up features have not been directly observed before in transition metals.