Collisions of Oq+ with neutral C-60: Charge transfer and fragmentation

Fragmentation of C-60 fullerenes by collisions with multiply charged Oq+ ions (1 less than or equal to q less than or equal to 7) has been studied experimentally for Oq+ collision energies of 1.16 keV amu(-1) For high projectile charges the potential energy of the projectiles is mainly responsible for the processes induced: the fragment spectra are dominated by multiply charged C-60(r+) parent ions and small fragment ions such as C+ and C-2(+). With decreasing projectile charge, fragmentation induced by the kinetic projectile energy becomes increasingly important, leading to a decreasing yield of surviving C-60(r+) ions and an increasing number of fragments C-n(+) with n in the range 2-12. Widths and shapes of the fragment peaks in the measured time-of-fight spectra allow us to determine the kinetic energy release for various fragmentation processes and to distinguish between evaporation of neutral C-2 molecules from vibrationally excited C-60(r+) ions on the one hand, and super-asymmetric fission into two charged fragments, on the other.