Stone-Wales transformations are thought to be the most likely route fo
r fullerene isomer interconversion. Several prototype reactions are in
vestigated using local density functional theory on C60Hm (m = 0, 1, 2
) and C-61 clusters. Transition state energies and geometries are calc
ulated. Adding hydrogen or carbon atoms to C-60 is found to catalyse t
he transformations.