Time-resolved relaxation dynamics of Hgn- (11 <or = n <or = 16,n = 18) clusters following intraband excitation at 1.5 eV.

Electron-nuclear relaxation dynamics are studied in Hg(n) (-) (11 <or= n <or= 16,n = 18) using time-resolved photoelectron imaging. The excess electron in the anion uniquely occupies the p band and is excited intraband by 1.53 eV pump photons; the subsequent dynamics are monitored by photodetachment at 3.06 eV and measurement of the photoelectron images as a function of pump-probe delay. The initially excited state decays on a time scale of approximately 10 ps, and subsequent relaxation dynamics reveal a smooth evolution of the photoelectron spectra towards lower electron kinetic energy over 50-100 ps. Qualitatively, the relaxation process is captured by a simple kinetic model assuming a series of radiationless transitions within a dense manifold of electronic states. All the clusters studied show similar dynamics with the exception of Hg(11) (-) in which the initially prepared state does not decay as quickly as the others. Copyright 2004 American Institute of Physics.