Coalescence kinetics of free and supported metal clusters

Coalescence kinetics of free and supported Ag, Cu, Ni and Pd clusters was studied by the Monte Carlo method with the Lennard-Jones plus Axilrod-Teller potential. A coalescence temperature was defined to characterize the coalescence of small metal clusters. The dependence of the cluster shape evolution on temperature and different stages during coalescence were studied. Firstly, neighboring clusters contacted each other through diffusion, and then neck regions formed between two neighboring clusters. Afterward the coalescing clusters deformed and finally relaxed to a new equilibrium shape. From the different shape evolution stages, it was found that the cluster growth followed the diffusion and coalescence mechanism, and the coalescence temperature was dependent not only on the cluster size but also on the average binding energy of the metal clusters.