An analysis of the second-order resonant Raman spectra of single-walled car
bon nanotubes using different laser energies in the range 1.58-2.71 eV is p
resented. Major emphasis is given to the overtones and combination modes as
sociated with the two dominant features of the first-order spectra, the rad
ial breathing mode and the tangential mode. Both of these modes, as well as
their second-order counterparts, are associated with resonant enhancement
phenomena arising from electron-phonon coupling to the unique one-dimension
al density of electronic states for the single-wall carbon nanotubes.