ROLE OF OFFSITE INTERACTIONS IN AUGER LINESHAPE ANALYSIS FROM CLOSED BANDS SYSTEMS

The Cini-Sawatzky theory of Auger CVV line shapes from solids and its extensions are based on single or multi-band Hubbard or Anderson models, retaining only the intra-atomic repulsion terms. In this work, we study the role of off-site interactions in closed bands systems. The local interaction terms are treated exactly, as usual, while off-site correlations are introduced as a self-energy-like correction, on perturbative grounds. Our main results is that the effect of off-site interactions must be taken into account to obtain simultaneous agreement for the shape and the energy position of the CVV spectra. This conclusion is supported by recent experimental evidence and affects the derivation of U values from line shape analysis.