Time-resolved photoelectron spectroscopy on small tungsten cluster anions

We have studied the dynamics of photoexcited tungsten cluster anions W-n(-) (n = 3,4, ..., 14) by means of time-resolved two-photon photodetachment spectroscopy. At an excitation energy of h nu (pump)=1.56 eV the photoinduced dynamics is mainly dominated by fast electronic relaxation processes. For the smallest clusters, i.c., W-3(-), W-4(-), and W-5(-), individual relaxation channels have been identified and resolved on a timescale well below 100 fs. The time constants for the decay of nascent and secondary electrons have been deduced from a Bloch model. Complete thermalization takes place for all clusters on a timescale of similar to 1 ps.