Kinetic energies of fragment ions produced in collisions of 2 MeV Si4+ with C-60

The fragmentation of C-60 induced by the impacts of 2 MeV Si4+ ions has been studied using time-of-flight techniques. From the peak profile analysis, initial kinetic energies of the fragment ions were obtained. For all the fragment ions investigated the energy distributions peaked at zero kinetic energy, and the total width of the distribution exhibited a strong dependence on the size of fragment ions. For the small fragment ions the kinetic energies decreased monotonously from 6 eV (C+) to 0.85 eV (C-12(+)), while for the multiply ionized parent ions and their daughter ions these values were nearly constant of about 0.04 eV. The results indicate that a large energy transfer from projectiles to C-60 takes place during collisions, resulting in high excitation followed by multifragmentation.