Shallow implantation of "size-selected" Ag clusters into graphite

We have investigated the implantation of Ag-N (N = 20-200) clusters into a graphite substrate over the range of energies (E) 0.75-6 keV using molecula r dynamics simulations. Mie find that after implantation the silver cluster s remain coherent, albeit amorphous, and rest at the bottom of an open tunn el in the graphite created by the impact. It is found that the implantation depth of the clusters varies linearly as E/N-2/3 We conclude that the clus ter is decelerated by a constant force proportional to its cross-sectional area. We also identify a threshold energy fur surface penetration associate d with elastic compression of the graphite substrate.