NE++C60 COLLISIONS - THE DYNAMICS OF CHARGE AND ENERGY-TRANSFER, FRAGMENTATION, AND ENDOHEDRAL COMPLEX-FORMATION

Interaction of Ne+ with C60 has been studied for collision energies ranging up to 100 eV. The dominant process is charge transfer, with C60+ accounting for 85% to 100% of the total product signal in this energy range. At 25 eV collision energy, C60-2n+ dissociative charge transfer products appear, accounting for approximately 13% of the total product signal at high energies. At approximately 25 eV, NeC60+, NeC58+, and NeC56+ all appear together, followed by a series of NeC60-2n+ products where n increases with increasing collision energy. These products are believed to be endohedral complexes, Ne@C60-2n+, where neon is physically trapped inside the fullerene cage. The production efficiency of the endocomplexes reaches a maximum of approximately 1.2% at 60 eV, and decreases to 0.5% at 100 eV. Modeling the results leads to the following picture of Ne+ + C60 collision dynamics: Charge transfer occurs in nearly all collisions, and is the only significant process for high impact parameters. At collision energies below approximately 25 eV, translational-to-internal energy transfer is inefficient, even for low impact parameter collisions. At higher energies, the inelasticity jumps to near 100%, leading to fragmentation of the nascent products. Both endohedral penetration and efficient energy transfer appear to require bond rupture in the C60.