Dephasing of image-potential states on Cu(100) upon CO adsorption measured by femtosecond two-photon photoemission spectroscopy

Abstract

The relaxation dynamics of the image-potential states of Cu(100) under the influence of CO adsorption is investigated by time-resolved Two-Photon Photoemission Spectroscopy (2PPE). Pure dephasing due to elastic scattering leads to a fast decay of quantum-beat patterns of energetically close-lying image states at already very low CO coverages. For higher CO exposure an increase in structural order is correlated with a decrease in pure dephasing rates.