Core-hole effects in the x-ray-absorption spectra of transition-metal silicides

We report systematic differences between the shape of the Si K x-ray-absorption spectra of transition-metal silicides and broadened partial densities of Si p states. We use a variety of calculations to show that the origin of these discrepancies is the core-hole potential appropriate to the final state. The effects can be successfully described by ab initio supercell calculations which explicitly include the presence of the hole in the excited state. A Clogston-Wolff model, with the ground-state partial densities of states at the site to be ionized as input data, can also describe the core-hole effect and is found to be a useful tool for the understanding of core-hole effects.