Characterization of single-walled carbon nanotubes containing defects from their local vibrational densities of states

The vibrational properties of defects in single-wall carbon nanotubes are investigated with an empirical dynamical model based on force constants fitted to graphite [Al-Jishi R, Venkataraman L, Dresselhaus MS, Dresselhaus G. Phonon modes in carbon nanotubules. Chem Phys Lett 1993;209:77-82]. The defected structures are: an isotopic substitution impurity in a chiral tube, a Stone-Wales defect in a series of (10, m) (m = 4, … , 10) nanotubes and in armchair tubes, and an intramolecular junction between (12, 0) and (9, 0) nanotubes. The study emphasizes differences in local vibrational densities of states (lVDOS) between perfect and imperfect nanotubes. lVDOS are computed with the recursion method. This is a first step towards a more complete approach for characterizing defects in carbon nanotube structures based on the recognition of localized vibrational fingerprint.