Prediction of the structures of clusters of C-60 molecules using an atom-atom interaction potential

Using a full 6O-site pairwise additive Lennard-Jones atom-atom potential to describe the interaction between C-60 molecules, we computed the lowest-energy structures of (C-60)(N) clusters up to N=20 and compared the results with predictions derived using Girifalco's spherical potential. The atom-atom intermolecular potential provides the more realistic description of the ground-state structures of the fullerene clusters. including the relative orientation of the C-60 molecules, but Girifalco's potential affords a good qualitative description of certain features. In particular, Girifalco's approximation is successful in predicting that (C-60)(13) is a highly stable, icosahedral cluster, and that a transition from icosahedral to decahedral structures occurs at a slightly larger cluster size.