Time-resolved photodissociation and threshold collision-induced dissociation of anionic gold clusters

Bond dissociation energies and fragmentation patterns of small gold anionic clusters, Au-n(-), are studied by the time-resolved photodissociation life time (n = 6, 7) and energy-resolved threshold collision-induced dissociatio n (n = 2-7) methods. The main fragmentation channels are found to be loss o f an atom or loss of a dimer. Time-resolved photofragmentation and both pro mpt and delayed electron loss are observed upon photon absorption. Dissocia tion energies are extracted using a statistical model for the unimolecular decomposition following collisional excitation or photoexcitation. Values o btained from the two methods overlap within the error bars. Dissociation en ergies for the loss of an atom from gold cluster anions, D-0(Au-n-1(-)-Au), show even-odd alternation. (C) 2000 Elsevier Science B.V. All rights reser ved.