Abstract
Interconversion between fullerene isomers can be achieved by rotation of atom pairs in the molecules about their mutual bond centre (Stone-Wales or pyracylene transformation). Our local spin-density functional theory based calculations show that although the activation energy for this process in C60 is very high—about 6.2 eV—the barrier is substantially reduced to 4.8 eV by the addition of a single hydrogen atom. Results for C60 H2 show similar behaviour and it is proposed that single carbon atoms can also catalyse these reactions. We conclude that the reduc- tion of energy barriers to Stone-Wales transformations by hydrogen, or possibly carbon, makes this a viable route for fullerene isomer interconversion.