COLLISION-INDUCED DISSOCIATION OF STORED GOLD CLUSTER IONS

The stability of gold cluster ions Au(n)+ (2 less-than-or-equal-to n l ess-than-or-equal-to 23) has been investigated via collision induced d issociation in a Penning trap. Threshold energies and dissociation cha nnels have been determined. The cluster stability exhibits a pronounce d odd - even alternation: Clusters with an odd number of atoms, n, are more stable than the even-numbered ones. Enhanced stabilities are fou nd for Au3+, Au9+, and Au19+ in accordance with the Clemenger-Nilsson and the deformed jellium model of delocalized valence electrons. Excit ed odd cluster ions with n less-than-or-equal-to 15 predominantly deca y by evaporation of dimers; all others decay by monomer evaporation. F rom the dissociation channels estimates of the binding energies are de duced.