THE DEFECT CHARACTER OF CARBON NANOTUBES AND NANOPARTICLES

Circuit mapping is employed to study the defect content of buckytubes and carbon nanoparticles. The topological analysis enables the connect ion with the well established defect theory of crystalline materials. The complementarity between defect models of two- and three-dimensiona l structures is considered as well as the significance of dislocation descriptions of these materials. In accordance with recent experimenta l observations, the possibility of three-dimensional hexagonal graphit ic stacking of atoms in these structures is examined through the intro duction of appropriate defects that are admissible in graphite. Defect s in graphene sheets introduce cap closure of isolated tubules and cha nges in tubule orientation, radius and helicity. In multilayered tubes , appropriate defects can accommodate curvature among adjacent sheets so that the ...ABAB... stacking is preserved. However, the graphite st acking is generally destroyed in multilayered caps owing to the lack o f appropriate graphite defects for their accommodation.