title    C60 FRAGMENTATION BY He+ AND He2+:
	ELECTRONIC VERSUS VIBRATIONNAL EXCITATION

authors
T. Schlathölter, O. Hadjar, R. Hoekstra, R. Morgenstern

affiliation
KVI Atomic Physics, Rijksuniversiteit Groningen, Zernikelaan 25, 9747 AA
Groningen

summary
 We have studied fragmentation and ionization of C60 by He+ impact over a
velocity range from 0.1 to 1 a.u., where a transition from vibrational to
electronic excitation is predicted. With increasing velocity we observe a
strong decrease of evaporative processes, i.e.  (C60-2m)r+ formation, and a
linearly increasing yield of small Cn+ (n<15) fragments. Apparently direct
vibrational excitation preferentially leads to evaporation, whereas electronic
excitation is responsible for multifragmentation.