The influence of the 4d bandwidth on the M_4,5N_4,5N_4,5Auger spectra of Ag in MgAg and AlAg alloys

The extent of the deviation of the Ag M4,5N4,5N4,5 Auger spectra from an atomic profile in pure Ag and its alloys with Mg and Al is shown to depend on the (4d) bandwidth. M. Cini's expression (1977) for the Auger electron spectrum, D( omega ), is used to relate the (4d) bands of these materials, determined from high-resolution photoelectron spectra, to the observed Auger spectra. An evaluation of D( omega ) for each component of the multiplet structure shows that the deviations of the M4,5N4,5N4,5 spectra from an atomic profile are due to reductions in the separation of the quasi-atomic parts of D( omega ) from atomic separations and a simultaneous transfer of intensity from the quasi-atomic to the broad parts of D( omega ). The theory predicts an absolute shift to lower kinetic energy of the Ag Auger spectra caused by the (4d) band. For the 1G4 component of the Ag Auger spectrum this shift lies between 0.2 and 0.5 eV.