Resonant Electron Transfer in Collisions between Two Fullerene Ions

Fullerenes are a direct link between atoms with discrete electronic energy levels and solids with a band structure and a well-defined surface. In this Letter, we report on the first ever experiment on resonant electron transfer in collisions between two fullerene ions. Total cross sections have been measured for the reaction ${\mathrm{C}}_{\mathrm{60}}^{\mathrm{+}}+{\mathrm{C}}_{\mathrm{60}}^{\mathrm{2}\mathrm{+}}\to {\mathrm{C}}_{\mathrm{60}}^{\mathrm{2}\mathrm{+}}+{\mathrm{C}}_{\mathrm{60}}^{\mathrm{+}}$ at center-of-mass energies ranging from 27 to 69 keV. Surprisingly, within the error bars, these cross sections are identical to the respective cross sections for ${\mathrm{C}}_{\mathrm{60}}^{\mathrm{+}}+{\mathrm{C}}_{\mathrm{60}}$ measured by Rohmund and Campbell [J. Phys. B 30, 5293 (1997)]. We show that the experimental data for both collision systems are very well reproduced by a quantum mechanical treatment of the reaction based on the concept of hole particles and the polarizability of the fullerene molecule.