Auger recombination and excited state relaxation dynamics in Hg(n)(-) (n=9-20) anion clusters.

Using femtosecond time-resolved photoelectron imaging, electron-hole pairs are created in size-selected Hg(n)(-) anion clusters (n=9-20), and the subsequent decay dynamics are measured. These clusters eject electrons via Auger decay on time scales of 100-600 fs. There is an abrupt increase in the Auger decay time for clusters larger than Hg(12)(-), coinciding with the onset of the transition from van der Waals to covalent bonding in mercury clusters. Our results also show evidence for subpicosecond excited state relaxation attributed to inelastic electron-electron and electron-hole scattering as well as hole-induced contraction of the cluster.