DISSOCIATION-ENERGIES OF TELLURIUM CLUSTER IONS FROM THERMOEVAPORATION EXPERIMENTS

The dissociation of tellurium cluster ions containing up to 40 atoms has been studied using unimolecular decay of thermoexcited clusters. Clusters with less than 10 atoms dissociate mainly by Te-2 loss. Larger clusters fragment by loss of Te-5, Te-6, or Te-7 species. As the cluster size increases, Te-5 loss becomes the predominent channel, showing a dissociation which smoothly evolves to the bulk behavior. The dissociation energies of mass selected Te-n(+), with n = 5-35, are deduced from the relative branching ratios of the competitive fragmentation channels. The changes in the observed neutral products are correlated to changes in the dissociation energies which are minima for cluster ion parents containing 13-25 atoms. (C) 1995 American Institute ofPhysics.