  We have studied photoluminescence (PL) and resonant Raman scatterings of
single-walled carbon nanotubes (SWNTs) consisting of carbon-13 (SW13CNTs)
synthesized from a small amount of isotopically modified ethanol. There was
almost no change in the Raman spectra shape for SW13CNTs except for a downshift
of the Raman shift frequency by the square-root of the mass ratio 12/13. By
comparing photoluminescence excitation (PLE) spectra of SW13CNTs and normal
SWNTs, the excitonic phonon sideband due to strong exciton-phonon interaction
was clearly identified with the expected isotope shift.
