Abstract
Local density functional total energy calculations have been performed on a series of I-h and non-l(h) fullerenes up to the C-840 onion (C-60@C-240@C-540) with a large basis. The ground states of C-300 and C-840 onions as well as their constituent single shells are facetted. The Ih facetted onion is found to have a small intershell energy of about 11 meV/atom comparable with that in simple hexagonal graphite. It appears that three routes to spherical particles: forcing spherical shape on I-h onions, introducing extra non-hexagonal rings into the outer shell and introducing an arbitrary misalignment between shells, all result in comparable increases in formation energy (0.08 eV/atom) above their aligned, facetted counterparts.