Excitation and Fragmentation Mechanisms in Ion-Fullerene Collisions

Electronic and vibronic excitations as well as fragmentation mechanisms in high energy ion ( ${\mathrm{H}}^{+}$, ${\mathrm{C}}^{+}$, ${\mathrm{Ar}}^{+}$) fullerene collisions are investigated within a fully microscopic approach, called nonadiabatic quantum molecular dynamics. The total kinetic energy loss of the projectile depends dramatically on ion mass, but, surprisingly, does not depend on the impact velocity for all ions in a certain range. This is in striking contrast to the predictions of the “stopping power” concept of solids, but explains apparently contradicting experimental observations. Signatures for nonstatistical fragmentation mechanisms are predicted.