More spherical large fullerenes and multi-layer fullerene cages

According to the experimental investigation, the carbon nano-particles have spherical multi-layer structure (also called onion-like carbon structure). Theoretically, the optimum structures of these large fullerenes contain hi ghly faceted shapes with icosahedral symmetry. This discrepancy in structur e may be attributed to the formation mechanism. Thus, a method is devised t o construct spherical large fullerenes (C-240 C-540, C-960, C-2160, C-2940, C-3840, C-3860) by using the triangular motif. The 5-7-5-7 shape defect is applied in this method for assembling the large spherical fullerenes which could transform the graphene sheet to a spherical motif via SW rearrangeme nt. The geometry-optimized structures of large spherical fullerenes have be en generated by molecular mechanics calculation. Then, the average radius a nd standard deviation of these large fullerenes were obtained to verify the spherical shape. The multi-layer fullerene with spherical shape was confir med by the TEM observation. According to the structure analysis, the distan ce between two neighboring encapsulating carbons is about 3.5 Angstrom, whi ch approximately coincides with the distance between two layers of graphite . The van der Waals force per carbon atom and of multi-layer fullerene with the spherical shape generated by force field calculation, predict their re lative stability. (C) 2001 Elsevier Science B.V. All rights reserved.