New highly charged fullerene ions: Production and fragmentation by slow ion impact

Fullerene ions, ${\mathrm{C}}_{60}^{\mathit{q}+}$, with q up to 9, have been observed in a study of their production by slow (v<0.5 au) impact of the projectiles ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}_{}^{4,5,8,12,16,17+}{}_{}{}^{}$, ${}_{}{}^{136}{}_{}{}^{}\mathrm{Xe}_{}^{27+}{}_{}{}^{}$, ${}_{}{}^{86}{}_{}{}^{}\mathrm{Kr}_{}^{28+}{}_{}{}^{}$, ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}_{}^{20,38,44,46+}{}_{}{}^{}$, and ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}_{}^{46+}{}_{}{}^{}$ on a neutral fullerene beam. The distribution of ion yields for each projectile is representable by a binomial form; variation of the biniomial fit parameters with projectile charge suggests the maximum positive charge for the fullerene ion. Correlations between the time of flight of first and second ions are shown to provide details of the fragmentation of fullerenes in close collisions. © 1996 The American Physical Society.