Relaxation dynamics of the Au3− and Au6− cluster anions

Using TR-2PPE spectroscopy, direct evidence is provided that excited states of sp-metal clusters can live longer than one nanosecond. For Au3−, in addition, the high time resolution in the present work allows us to monitor the wave-packet motion in the real time scale. The relaxation times of the Au clusters are estimated to be longer than those of the Al clusters with similar sizes by about three orders of magnitude. This result is attributed to the larger gaps between various energy levels in Au clusters originating from relativistic effects, which markedly reduce the e–e scattering rates.