Anti-Stokes Raman spectra of single-walled carbon nanotubes

An analysis of the Stokes and anti-Stokes resonant Raman spectra of single- walled carbon nanotubes (SWNT's) using different laser energies in the rang e 1.49 less than or equal to E(laser)less than or equal to 2.19 eV shows ma jor differences in the tangential band spectra for the Stokes and anti-Stok es processes for Selected E-laser values. These differences arise from the differences in the one-dimensional density of electronic states for metalli c and semiconducting nanotubes. This observation allows selection of E-lase r to excite only semiconducting or only metallic nanotubes in the Stokes an d anti-Stokes spectra.