COLLISION-INDUCED FRAGMENTATION AND RESILIENCE OF SCATTERED C+60 FULLERENES

Fragmentation of positively charged Buckminster fullerenes scattered from a surface of pyrolytic graphite is studied. The ions are produced by laser desorption, accelerated, directed onto the surface and detected after the collision by time of flight mass spectroscopy. Velocity distributions of the scattered C60+ ions and of dissociated scattered ions are observed to be bimodal. The slower part has a narrower velocity distribution and is scattered more towards the surface normal in comparison to the faster part. Two interaction mechanisms are proposed to describe the experimental findings. Common to both is the transfer of incident kinetic energy into final thermal energy followed by substantial fragmentation. The differences between both mechanisms are explainable under the assumption that either chemical bonds are formed between cluster and surface and broken again when the cluster receeds (low velocity) or not (higher velocity).