A quantitative study was made of the diffusion of spherical antimony clusters deposited on graphite surfaces. The experimental structures obtained during deposition were compared to predictions of recent computer models, and very good agreement was found. From this comparison, the diffusion coefficient of large antimony clusters containing around 2300 atoms moving on a graphite substrate could be obtained. It was found that the results (figure 14) could be described by:

D (cm2/s) = 1.6 x 104exp[-0.7(eV)/kT]

The large value of D0 suggested that the diffusion could not be explained by a simple atomic activated process, but may rather involve collective motions of the atoms of the cluster.

Experimental Observation of Fast Diffusion of Large Antimony Clusters on Graphite Surfaces. Bardotti, L., Jensen, P., Hoareau, A., Treilleux, M., Cabaud, B.: Physical Review Letters, 1995, 74[23], 4694-7