1. Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180–3590, USA.
2. IPICYT, Av, Venustiano Carranza 2425-A, San Luis Potosı́ 78210, SLP, México.
3. Fullerene Science Centre, University of Sussex, Brighton BN1 9QJ, UK.
4. Laboratoire des Nanostructures, ISIS, UMR 7006, Universite Louis Pasteur, 4 rue B. Pascal, 67000 Strasbourg, France.