Photon energy and core hole lifetime dependences of Ag high energy Auger satellites

Abstract

Understanding metallic response to the presence of a dynamic, localized perturbation, such as a finite lifetime core hole, has been the theme of many studies. Although, in XPS of such metals as Ni and Pd, shake-up satellites are common, in Auger spectroscopy, an intrinsic laboratory of many-body effects, the most extensively studied metal, Cu, manifests LVV satellites which are associated with Coster–Kronig (CK) transitions. Unambiguously identified shake-up satellites have been observed in the L 123M 45M 45 spectra of the 4d metals, studied with conventional X-ray sources and, in the L 3 threshold region, with synchrotron radiation. There remain questions concerning the origin of these satellites and their relation to the corresponding XPS spectra. Here, we report a study of the Ag L 23M 45M 45 spectra as a function of photon energy and demonstrate the evolution of the satellite spectra. The change of the satellite shapes with photon energy is directly related to the validity of the sudden approximation. Correlation of the satellite spectra with core level lifetime indicates the influence of core hole dynamics. From the experimental systematics, it becomes clear that isolation of CK effects is very difficult.