TIME-RESOLVED KINETIC-ENERGY RELEASES FOR C-60(CENTER-DOT-]C-58(CENTER-DOT+)+C-2())

Time-resolved kinetic energy release (KER) measurements were performed on an ion trap/reflectron mass spectrometer. The average KER for C-2 evaporation from C-60(.+) was observed to decrease with increasing pre cursor ion lifetime. This constitutes proof that the KER is due to the non-fixed energy in the transition state rather than to a reverse act ivation energy, and that the reaction takes place via a loose transiti on state. The data will be extended to longer lifetimes and to other c luster systems, and modelled by finite heat bath theory (FHBT). The po ssibility of experimentally observing phase transitions in cluster sys tems can now be explored. (C) 1997 Elsevier Science B.V.