Collision-induced dissociation of C₆₀^-: effect of energy-coupling processes on the dissociation dynamics

Abstract

Dissociation of C₆₀^- ions induced in 30 keV collisions with atomic and molecular gases has been studied. The pattern of negativeion formation from C₆₀^- precursors is found to be distinctly different from that obtained for positive-ion fragments from C₆₀⁺ precursors in that the collision-induced dissociation spectrum in the former case is dominated by small negative clusters, presumably of linear geometry, Simple arguments utilizing the relationship of electrostatic properties of different molecular structures to their electron affinities and ionization energies have been invoked to rationalize these observations. The difference in the dissociation dynamics of C₆₀^- and C₆₀⁺ ions is discussed in terms of competition between different energy-coupling schemes involving either electronic degrees of freedom or nuclear (vibrational) degrees of freedom.