Charge-exchange collisions of C-60(z+): A probe of the ion charge distribution

We present Paul trap measurements of charge-exchange collisions of Li, Cs and C-60 with C-60(z+) ions (z=1-3) at thermal energies. Surprisingly, the measured charge-exchange rates for each neutral species are not proportional to the ion charge z as would be expected for Langevin collisions involving a uniformly charged ion. The relative rates can be reproduced by a model based on a symmetric distribution of point charges that are free to move on the ion surface during the neutral trajectory. Such behavior can be attributed to static and possibly dynamic Jahn-Teller effects in C-60(z+) ions. (C) 1997 Elsevier Science B.V.