RELAXATION DYNAMICS OF C-60

The relaxation dynamics of C-60 from high-energy isomers to Buckminste rfullerene is examined using a master equation approach. An exhaustive catalog of the C-60 fullerene isomers containing only five- and six-m embered rings is combined with knowledge of the Stone-Wales rearrangem ents that connect all such isomers. Full geometry optimizations have b een performed for all the minima and the transition states which conne ct them up to six Stone-Wales steps away from the global minimum. A de nsity-functional tight-binding potential was employed to provide a qua ntum mechanical description of the bonding. The resulting picture of t he potential energy landscape reveals a ''weeping willow'' structure w hich offers a clear explanation for the relatively long relaxation tim es observed experimentally. We also predict the most important transie nt local minima on the annealing pathway. (C) 1998 American Institute of Physics. [S0021-9606(98)50940-3].