C59-ion formation in high-energy collisions between cold C-60 and noble gases

A high kinetic energy beam of C^-₆₀ ions produced by electrospray was collided with He and Ne targets, and the cross sections for production of positive and negative fragment ions were determined. In these experiments we observed both C⁺₅₉ and C^-₅₉ fragment ions with He and Ne target gases. Since the initial internal energy of the ions is low, it is possible to knock out one carbon atom from the fullerene cage and thereby form C₅₉ ions with lifetimes long enough to allow them to be detected (of the order of 10 μs). Comparisons with molecular dynamic simulations show that the cross sections for formation of C^-₅₉ and also C^-₅₈ can be explained as the result of a ``prompt'' knock-out process.