A similar impact on the 1ML surfaces leads to the fullerene picking up 1 H and 2 Si atoms. The collision results in one bond being broken in the C 60 and causes it to spin. The damaged molecule remains bound to the three additional atoms and travels away from the surface. Impact on the 2ML surface results in no reaction and no damage to either the fullerene or the surface. We find that the energy threshold at which a fullerene is reflected from the surface is dependent upon both the surface coating and the angle of incidence.
Reflection can occur at higher incident energies if the angle of incidence is away from normal.
When reflection does occur, the collision is highly inelastic. The dangling bonds on the bare surface make it reactive and the fullerene is never reflected at incident energies above 100 eV. Hydrogen termination of the surface does not greatly reduce its reactivity with the fullerene. The large momentum of the C 60 means that the light H atoms are easily knocked from their surface positions, allowing reaction with the exposed Si atoms. The 1ML surface is less prone to reaction with the molecule than the 2ML surface if incidence is at angles close to normal. This is because the SiH 2 units on the 2ML surface are easily displaced, allowing the fullerene to penetrate the surface.