Interaction of slow (100 ev/atom) carbon clusters with gold: Penetration properties and collision cascades

Abstract

The interaction of carbon clusters of variable size with thin gold targets has been analyzed by molecular dynamics simulation. The initial energy was 100 eV per cluster atom. Only a minor difference was found between the mean energy loss of transmitted cluster atoms and individual bombarding carbon atoms. The energy spectrum of transmitted cluster atoms is much broader than for atomic bombardment. In particular, a substantial fraction of the cluster atoms is transmitted with energies higher than their initial energy. This effect has been traced to collisions between cluster atoms. Similar, yet less pronounced effects were also found for reflected cluster atoms. The angular distribution of transmitted cluster atoms shows a sharp dip in the forward direction while their average energy in the forward direction even exceeds the initial energy per atom. Recoiling target atoms may achieve kinetic energies up to more than twice the maximum recoil energy in a single elastic collision. This effect has been traced to mu ltiple hits by different cluster atoms.