Line shape of the Ag M4,5VV Auger spectra measured by Auger-photoelectron coincidence spectroscopy -: art. no. 155102

We present high resolution Ag M5VV and M4VV Auger spectra obtained in coincidence with 3d(5/2) and 3d(3/2) core photoelectrons, respectively. Auger photoelectron coincidence spectroscopy (APECS) was used to separate these overlapping Auger lines and determine the intrinsic line shape of each spectrum. As the on-site Coulomb correlation energy U of Ag is comparable to twice the 4d bandwidth, 2W, (i.e., U/2W similar to1), the coincidence Auger spectra exhibit both atomiclike and bandlike character. We find that whether considered separately or in combination, neither bandlike nor atomiclike line shapes give a satisfactory account of these Auger spectra. Instead, the intrinsic Ag M5VV and M4VV line shapes are well described by the Cini-Sawatzky theory when it is applied separately to each component of the multiplet structure of the 4d(8)5s(2) Auger final state. A fit to the APECS data indicates that the correlation energy the (1)G(4) multiplet is 4.8+/-0.1 eV. Furthermore, our analysis indicates that the missing intensity in the vicinity of the F-3(4) multiplet in the Ag M5VV Auger line, which has been noted in previous studies, results from a shift in the spectral weight of this multiplet component to higher kinetic energy, into the bandlike region of the spectrum.