STRUCTURAL AND VIBRATIONAL PROPERTIES OF FULLERENES AND NANOTUBES IN A NONORTHOGONAL TIGHT-BINDING SCHEME

A simple, computationally efficient method for the evaluation of struc tural and vibrational properties of carbon is presented. The scheme is based on the generalized tight-binding molecular dynamics technique a pplicable to covalent systems. The force constants for the evaluation of vibrational modes are obtained by employing analytic second derivat ives of the electronic structure Hamiltonian matrix elements. This met hod, while providing better accuracy than conventional schemes, greatl y expedites the determination of vibrational modes for large size clus ters. The efficacy of the method is demonstrated by application to ful lerenes and nanotubes. Good agreement is obtained with experiment for bond lengths and vibrational frequencies for these systems. (C) 1996 A merican Institute of Physics.