Adatom Diffusion and Interactions: Pd on W(110)

Abstract

Three-atom interaction energies have been estimated from the observed linear-to-island transformation of Pd clusters and from the measured interaction energies of Pd pairs. In this, three-atom interaction energies corresponding to two different configurations, linear and triangle, have been obtained for the first time. It has been found that the magnitude of the three-atom interaction energy for the linear configuration, F$\sb{\rm 3,lin}$, is large. The large three-atom interaction energy of the linear configuration is responsible for the observed stability of linear chain structures of small Pd clusters and for the linear-to-island transformation when the size of the cluster increases. This study has shown that many-atom interactions play a crucial role in the cohesion and structure of nuclei in the early stages of crystal growth and hence significantly influence the entire growth process.