Stability and fragmentation of multiply charged clusters of fullerenes

Stability and fragmentation of multiply charged clusters of fullerenes ( C 60 ) n z + are theoretically studied for 2 ⩽ z ⩽ 7. The energy barriers for various fragmentation channels are calculated within the framework of the contact sphere model. For all the cases studied, an emission of a monomer ion C 60 + is found to be energetically the most plausible decay channel for multiply charged clusters. Experimentally measured appearances sizes have been reproduced within a considerable accuracy. Although the liquid drop model essentially explains the appearance sizes, deviations due to geometric shell effects are predicted for highly charged clusters (z ⩾ 6).