The diffusion and rotation of Pt nanoclusters supported on graphite were studied. Using molecular dynamics simulation, it was revealed that the supported Pt clusters had two types of bottom layer: an hexagonal lattice and a rectangular lattice. The diffusion rate of the Pt clusters depended mainly upon the type of bottom layers. This observation was explained by the periodic lattice matching between the bottom layer and the graphite. In addition to lateral diffusion, it was found that the Pt clusters with a rectangular or mixed lattice tend to rotate or wag on the z axis. By using the rotation rates and total movements of all atoms, it was shown that the rotation of a Pt cluster could be induced by the difference in the diffusion rates for the different types of bottom layers. This outcome was well in accord with the proposed diffusion mechanism.

Molecular Dynamics Simulations of the Diffusion and Rotation of Pt Nanoclusters Supported on Graphite. Ryu, J.H., Seo, D.H., Kim, D.H., Lee, H.M.: Physical Chemistry Chemical Physics, 2009, 11[3], 503-7