Modeling CoreHole Screening in CoreExcitation Spectroscopies

We consider screening of the core-hole potential experienced by the ejected electron in core-excitation processes. This potential affects near-edge structure strongly, but it appears difficult to consistently obtain reliable screened core-hole potentials without substantial computation. Screening effects have both atomic and solid-state (or molecular/cluster) contributions. We emphasize aspects that must be true of "correct" screening models, in an attempt to circumvent the need to carry out full-scale randomphase approximation (RPA) or self-consistent-field calculations of the screening. We present and discuss three spectra computed with RPA and model screened potentials, suggesting ideas to be considered in future work developing screening models.