Quasi-atomic MVV auger spectra of Pd metal: cascade processes

The study of Auger spectra of atoms affected by cascade processes has attac ted considerable interest because of the availability of tunable photon ene rgies of synchrotron radiation. We present results for the XAES MW spectra of Pd and Ag measured, with synchrotron radiation, before and after ionizat ion of the respective L-3 levels. The respective spectra change dramaticall y upon ionization and we attribute the extra structure produced after ioniz ation as corresponding to the M45M45-->M45VV transition, which is subsequen t to the L3M45M45 transition. The extra structure for Pd is markedly simila r to that of Ag, indicating its quasi-atomic nature. These results allow us to interpret the extra spectral structure of Pd as quasi-atomic and to att ribute its origin to a bound state of the two final-state holes in the full Pd d-band. We believe the filling of the band to be produced by d-valence electrons which screen the two initial M-45 holes. (C) 2001 Elsevier Scienc e B.V. All rights reserved.