Energy loss of fast Li and Si projectiles in electron loss collisions with C 60

Abstract

We have studied the multifragmentation of C 60 under electron loss collisions of 2 MeV Li 0–2+ and Si 0–4+ projectiles. Assuming the Bragg’s additivity rule and using available stopping power program codes, electronic energy deposition into a C 60 molecule has been calculated for six and 15 different electron loss collisions of Li and Si projectiles, respectively. To do this, the impact-parameter dependent ionization probability of incident particles was calculated semiclassically. The calculated energy deposition was found to have a remarkably simple relationship with the degree of C 60-multifragmentation obtained experimentally for Si projectiles. From comparisons between calculations and experiments, it is also suggested that the stopping power partition rate leading to internal excitation of C 60 may be significantly different for Li and Si projectiles.