A study was made of the effect of surface defects upon the electronic configuration of adsorbed Pt atoms and Pt8 clusters. It was found that surface diffusion was strongly reduced by depositing Pt and Pt8 into a thin rare-gas layer. In this configuration, a very narrow adatom Pt 4f spectrum was found at an exceptionally small binding energy; similar to Pt surfaces. Both the adatom and cluster spectra were strongly shifted towards higher binding energies, when allowed to diffuse towards defects such as step edges. The strong shifts reflected a chemical reaction at the step edges, and were suggested to be part of the particle-size dependent binding energy shifts which were typically observed for transition metal clusters that were grown on the surface of graphite.

Strong Influence of Defects on the Electronic Structure of Pt Adatoms and Clusters on Graphite. K.Fauth, M.Hessler, D.Batchelor, G.Schütz: Surface Science, 2003, 529[3], 397-402