The first and second-order Raman spectra were measured for single-wall carb
on nanotubes (SWNTs). Eighteen first-order Raman spectral lines and seven s
econd-order Raman spectral lines were observed. Spectral lines predicted by
theory were almost fully detected. Positions of the spectral lines observe
d are well coincident with theoretical values. The number of Raman active p
honon modes and the second-order Raman spectral lines for high-purity SWNTs
observed is the biggest up to date.