Size distributions of fullerene surface clusters

We present an exactly solvable generalization of the rate equation model for irreversible growth with size-independent capture numbers which includes desorption of monomers. It is shown that the universal size distribution shapes depend on the sole parameter, the ratio between the characteristic diffusion and adsorption areas. We perform a statistical analysis of the scanning tunneling microscopy images of C60 clusters deposited onto In-modified Si(1 1 1)√3 × √3-Au surfaces at different temperatures and deduce the experimental size distributions. These distributions have an essentially asymmetric shape with a much faster decay toward larger sizes. Fitting the data with theoretical distribution shapes yield the estimates for some important kinetic parameters, in particular, the temperature-dependent diffusion lengths and effective lifetimes of C60 monomers.