Line shape variations of Ag auger shake-up satellites outside the resonance regime

In recent publications, unambiguously identified shake-up satellites have b een observed in the L123M45M45 spectra of 4d metals, studied with conventio nal X-ray sources and, in the L-3 threshold region, with synchrotron radiat ion. There remain questions concerning the origin of these satellites and t heir relation to the corresponding X-ray photoelectron spectroscopy (XPS) s pectra. We report here a study of the Ag L23M45M45 spectra as a function of photon energy and demonstrate the evolution of the line shapes of the sate llite spectra. The transition from the adiabatic to sudden approximation re gimes appears to occur at around 80 eV above threshold, which is much less than expected for plasmon satellites. These results may reflect the influen ce of quasi-atomic screening, as opposed to metallic screening. The experim ents were performed using the SXS-beamline at the National Synchrotron Labo ratory of Brazil (LNLS). (C) 1999 Elsevier Science B.V. All rights reserved .