Abstract. The stable configurations of small fullerenes (C₂₀ and C₂₈) encapsulated inside single wall carbon nanotubes (SWNTs) of different diameters were investigated by molecular dynamics simulations. The interactions between carbon atoms were described by a combination of the many-body Brenner potential with the Lennard-Jones (LJ) potential. We observed that the filling of small fullerenes into nanotubes with diameters larger than 10.85 Å ((8, 8) SWNT) is an exothermic process. During the annealing process the fullerenes arrange themselves into complex phases, which may be one-(chain), two-(zigzag) or three-dimensional, depending on the tube diameter. This tube size dependence is very similar to that of C₆₀, which has been experimentally observed. A comparison with the prediction of the hard-sphere model also finds a satisfactory level of consistency, indicating the dense packing nature of fullerene configurations in SWNTs.

Print publication: Issue 8 (28 April 2006)
Received 25 November 2005, in final form 7 February 2006
Published 15 March 2006