[en] Carbon bombardment of graphite and diamond is investigated by molecular dynamics simulations using a many-body potential to describe the low energy interactions splined to a Moliere potential which describes the hard collisions. It is found that no ejection takes place from the perfect graphite {1000} face at bombardment energies of 100 eV and that at normal incidence the yield is below 1% up to 600 eV. At oblique incidence corresponding to the maximum yield angle, the yield can be in excess of ten times that at normal incidence and a much larger proportion of dimer and trimer molecules are ejected. The bulk terminated diamond surfaces are found to be less resistant to erosion than graphite with as much as 23% of material ejected at normal incidence being in the form of dimers. (orig.)