RAMAN INTENSITY OF SINGLE-WALL CARBON NANOTUBES

Using nonresonant bond-polarization theory, the Raman intensity of a s ingle-wall carbon nanotube is calculated as a function of the polariza tion of light and the chirality of the carbon nanotube. The force-cons tant tensor for calculating phonon dispersion relations in the nanotub es is scaled from those for two-dimensional graphite. The calculated R aman spectra do not depend much on the chirality, while their frequenc ies clearly depend on the nanotube diameter. The polarization and samp le orientation dependence of the Raman intensity shows that the symmet ry of the Raman modes can be obtained by varying the direction of the nanotube axis, keeping the polarization vectors of the light fixed. [S 0163-1829(98)06908-2].