Collisions between ${\mathrm{C}}_{60}^{-}$ and alkali-metal ion are investigated by an ab initio molecular dynamics simulation at 1000 K. When ${\mathrm{Li}}^{+}$ with kinetic energy $\sim 5\mathrm{eV}$ hits the center of a six-membered ring of ${\mathrm{C}}_{60}^{-}$, Li@${\mathrm{C}}_{60}$ is created. If either the kinetic energy is lower or the collision occurs off center, the ${\mathrm{Li}}^{+}$ ion stays outside, and ${\mathrm{C}}_{60}$ is deformed by the shock. In some cases, several bonds of ${\mathrm{C}}_{60}$ break after the bombardment; this may make the insertion of alkali-metal ion easier.

• Received 25 September 1995

DOI:https://doi.org/10.1103/PhysRevLett.76.3590