Plasmon effects on core level spectra of adsorbates

The X-ray photoemission current for an adsorbate core level is calculated for a model which allows the screening of the core hole, both by charge transfer to the adsorbate and by coupling to the surface plasmons. The calculations are performed within a (nonlinear) time dependent Hartree-Fock scheme. The charge transfer dominates the long time behavior, while the surface plasmons lead to important qualitative changes of the spectra in the weak chemisorption and physisorption case via their importance for the short time response.