Intrinsic and extrinsic loss contributions in X-ray induced photo- and Auger electron emission from surface layers of solids

We investigate the energy loss process leading to the excitation of bulk and surface plasmons during the emission of electrons in X-ray photoemission spectroscopy (XPS) and in Auger electron spectroscopy (AES), in the presence of a solid surface. We take into account the effects due to the sudden creation of the electron-hole pair, to the electron transport and to the residual hole, as well as the proximity of the surface. We use the dielectric response theory for describing the material, and the specular reflection model for describing the process. The results illustrate that, from the theoretical point of view, to separate extrinsic and intrinsic contributions could be ambiguous (in terms of independent processes) due to interference effects between the photoelectron and the photohole present in both processes. These effects are intrinsic to the process and cannot be avoided. Besides, we have taken into account the distance from the surface in which the process develops. The proximity of the surface adds more interference to those processes.