MOLECULAR-DYNAMICS SIMULATIONS OF KEV PARTICLE BOMBARDMENT - CORRELATION OF INTACT MOLECULAR EJECTION WITH ADSORBATE SIZE

Molecular dynamics simulations employing a reactive many-body potentia l of the keV particle bombardment of small hydrocarbon molecules adsor bed on a metal surface have been performed. The simulations predict th e occurrence of considerable lateral motion of particles in the region right above the surface. For adsorbates such as CHx, dominant ejected species are an H atom or the intact adsorbate as there are only two u nique bonds to sever. Molecules that extend further above the surfaces are exposed to more collisions from laterally moving particles and co nsequently there is more fragmentation and the dominant ejected specie s is usually not the original adsorbate.