Femtosecond dynamics of electronic excitations at metal surfaces

The dynamics of charge transfer and electronic excitations are of fundamental importance in many areas of surface physics. At metal surfaces electronic relaxation occurs on the timescale of femtoseconds due to the strong resonant coupling with a continuum of substrate excitations. Recent advances in ultrafast laser sources and the development of nonlinear laser-based surface probes, in particular the technique of time-resolved photoemission, now make it possible to investigate the electron dynamics at surfaces directly in the time domain. Some of the recent progress in this field is exemplified by the ultrafast dynamics of image-potential states on Cu(111) and their interaction with rare gas adsorbates.