Vibrational modes of single-wall carbon nanotube intramolecular junctions were calculated using the Brenner reactive empirical bond order potential, based upon which non-resonant Raman spectra were calculated using the empirical bond polarizability model. It was found that the Raman peaks introduced by pentagon defects lay outside of the G-band of the single-walled carbon nanotube. Thus the high-frequency part of the Raman spectra of the single-walled carbon nanotube intramolecular junctions could be used to determine their detailed geometrical structures experimentally. The intensity of the Raman spectra had a close relationship to the number of pentagon defects in the single-walled nanotube intramolecular junctions. Using the Descartes-Euler polyhedra formula, the number of heptagon defects in the single-walled nanotube intramolecular junctions could also be determined. First-principles calculations were also performed which confirmed the results obtained using the reactive bond order potential. The G-band width of the intramolecular junctions could reflect the length of its transition region between pentagon and heptagon rings.

Raman Characteristic Peaks Induced by the Topological Defects of Carbon Nanotube Intramolecular Junctions. G.Wu, J.Dong: Physical Review B, 2006, 73[24], 245414