Ionization and fragmentation of fullerene ions by electron impact

Absolute cross sections for the electron-impact multiple ionization and fragmentation of negatively charged fullerene ions C(n)(-) (n = 60, 70, 84) --> C(n-m)(q+) (q = 1, 2, 3 and m = 0, 2, 4) have been measured for electron energies up to 1 keV A scaling law has been observed for the magnitude of the ionization cross sections. Furthermore, the multiple ionization of a fullerene anion is found to be a sequential process. A novel ionization mechanism is proposed which can be expected to be valid also for other negatively charged molecular or cluster ions.