Dissociation pathways of doubly and triply charged gold clusters

Collision induced dissociation is applied to study the fragmentation channe ls of multiply charged gold clusters, Au-N(2+), size N = 7-35, and Au-N(3+) , N = 19-35, stored in an ion cyclotron resonance (Penning) trap. The main dissociation pathways are neutral monomer evaporation, Au-N(Z+) --> Au-N-1( Z+) Au, for the larger and fission into a charged trimer plus the remaining cluster, Au-N(Z+) --> Au-N-3((N-1)+) + Au-3(+), for the smaller clusters. In the intermediate cluster size region an odd-even alternation of the two competing decay pathways is observed. In addition, for some specific cluste r sizes there are indications of neutral dimer evaporation, Au-N(Z+) --> Au -N-2(Z+) + Au-2, and of extremely asymmetric fission of the form Au-N(Z+) - ->Au-N-1((Z-1)+) + Au+.