Time constants for the decay of elementary optical excitations in surface bound Na clusters

The decay of laser-induced collective electronic excitations in large, surface bound metallic clusters is investigated via linear extinction, desorption, near-field time-of-flight and time-resolved second harmonic measurements. The experimental observations suggest a model that invokes a decay of the initial plasmon excitation within tens of femtoseconds into single electron excitations and electron–phonon coupling on a time scale of picoseconds. Finally, following coupling to substrate vibrations and with a delay of tens of nanoseconds, atoms desorb from the clusters with low kinetic energies.