Theoretical study of nanotube growth in terms of frontier density distribution

For carbon nanotubes with open end, the relation between the distribution o f frontier orbitals and the edge structure was studied by the Huckel and ab initio molecular orbital methods. When the edge of a nanotube takes a zigz ag form, the frontier orbitals localize at the edge part irrespective of th e tube length, and continuous growth can be expected according to the front ier electron theory; when the edge takes an armchair form, the frontier orb itals delocalize all over the tube surface, disfavoring the nanotube growth . These results coincide with the experimental observation by Sattler et al . (C) 2001 Elsevier Science B.V. All rights reserved.