ENERGETIC FULLERENE INTERACTIONS WITH A GRAPHITE SURFACE

The interaction of C60 molecules with a graphite surface is modelled using molecular dynamics. At normal incidence it is found that the C60 molecule is reflected intact at energies up to about 250 eV and a depression wave spreads radially from the point of impact across the graphite surface preceded by hypersonic fronts which transmit small amounts of energy. At energies of 1 keV and 6 keV the molecule implodes as it enters the crystal creating a particle of dense amorphous carbon beneath the surface. Very little sputtering occurs at normal incidence at energies of up to 6 keV. At 6 keV and at an incidence angle of 60-degrees to the normal, the molecule breaks up on impact and some sputtering is observed. At 15 keV the sputtering yield increases and the surface ruptures in the central region where carbon clusters and chains are ejected. Outside this region the bonds remain intact but surface begins to separate from the second layer with a raised travelling wave propagating from the impact point.