Size selected cluster deposition on well characterized surfaces: Ag_n/Pd(100)

We study the deposition of Ag ions, and size selected Ag/sub 7/ and Ag/sub 19/ cluster ions on Pd(100) at total kinetic energies of 20 eV and 95 eV using thermal energy atom scattering and molecular dynamics simulations. We find that at all energies Ag atoms are implanted into the substrate and Pd atoms are ejected in the adlayer. The experimental results in the case of Ag/sub 7/ can be understood in taking into account both implantation of Ag atoms and heavy fragmentation. In the case of Ag/sub 19/ the deposition leads at low temperature to non compact structures localized around the impact point. We propose a model in which morphology changes take place between 200 K and 300 K resulting in well separated compact structures formed of Ag and Pd adatoms.