Experimental evidence for molecular ultrafast dissociation in O-2 clusters

Resonant Auger spectra of O-2 clusters excited at the O1s edge are reported. After excitation to the repulsive 1s(-1)3 sigma* state, the resulting resonant Auger spectrum displays features that remain constant in kinetic energy as the photon energy is detuned. The shift between known atomic fragment features and these features is consistent with that observed for atoms and clusters in singly charged states in direct photoemission. These findings are strong evidence for the existence of molecular ultrafast dissociation processes within the clusters or on their surface