Thermal road for fullerene annealing

The Stone-Wales transformation has been proposed as a basic process for ring rearrangement in a fullerene cage and, consequently, for annealing fullerene structures down to the ground state. We present a new, thermally activated, mechanism for the Stone-Wales transformation. This mechanism, found in dynamical simulations of C60, involves a multi-step isomerization transition process in contrast with the commonly assumed single-step mechanism. The step-to-step energy barriers found in the multistep process are much lower than the reported ones for single-setp process. We also present a dynamical simulation of the thermal fullerene-to-graphite reconstruction of C60 of relevance to the growth of fullerenes. The two thermal processes presented open new roads for investigating the formation and annealing mechanisms of different carbon structures.