COLLISION-INDUCED DISSOCIATION OF C60- - EFFECT OF ENERGY-COUPLING PROCESSES ON THE DISSOCIATION DYNAMICS

Dissociation of C-60(-) ions induced in 30 keV collisions with atomic and molecular gases has been studied. The pattern of negative-ion form ation from C-60(-) precursors is found to be distinctly different from that obtained for positive-ion fragments from C-60(+) precursors in t hat the collision-induced dissociation spectrum in the former case is dominated by small negative clusters, presumably of linear geometry. S imple arguments utilizing the relationship of electrostatic properties of different molecular structures to their electron affinities and io nization energies have been invoked to rationalize these observations. The difference in the dissociation dynamics of C-60(-) and C-60(+) io ns is discussed in terms of competition between different energy-coupl ing schemes involving either electronic degrees of freedom or nuclear (vibrational) degrees of freedom.