CARBON-ATOMS CATALYZE FULLERENE GROWTH

The fullerene road to C-60 must proceed through isomers which do not o bey the Isolated Pentagon Rule (IPR). Stone Wales (SW) transformations are required to redistribute the pentagons to obtain the almost exclu sively observed IPR icosahedral C-60. We find a very high barrier for these transformations (over 6 eV), which make their occurrence rare du ring the annealing phase of C-60 formation. Earlier we reported that t he presence of a loosely bound single carbon atom reduces this barrier to 3.9 eV, making frequent pentagon rearrangements possible. Here we review this process and show how carbon atoms bind preferentially to p aired pentagon regions, diffuse easily and exchange with C-60 host ato ms.