ENERGETICS OF BENT CARBON NANOTUBES

Several junctions between different nanotubes have been constructed wh ich preserve the C sp(2) honeycomb lattice with the sole insertion of a pentagon and a heptagon. This construction bends the structure at an angle that depends on the distance between the pentagon and heptagon. The atomic structure of these systems was optimized with empirical in teratomic potentials. The nanotubes on both sides of the junctions wer e treated as infinitely long. Local sigma+pi electron densities of sta tes were computed locally in the interfacial region with a tight-bindi ng Hamiltonian. From this, the electron energy of the junctions was co mputed and compared to that of the separated nanotubes. It is found th at the energy of a pentagon-heptagon defect in the graphitic tubular n etwork is around 6 eV. [S0163-1829(98)04504-4].