Time-resolved core-hole decay and sideband structure in laser-assisted photoemission from metal surfaces

We present a theoretical investigation of sideband structures in laser-assisted photoelectron spectra that result from the illumination of an adsorbate-covered metal surface with an ultra-short soft X-ray and a delayed IR laser pulse. We show how the relaxation dynamics of core level holes in the adsorbate atoms can be deduced from a temporal shift in the intensity of the first sideband peaks of adsorbate-Auger electrons relative to conduction band photoelectrons. Our results also include a characteristic sub-sideband structure in the photoelectron spectra that is due to the interference of core-level electrons which are emitted from different layers in the solid.