Relative intensities of resonant Raman spectral features, specifically the radial breathing mode (RBM) and G modes, of eleven chirality-enriched single-wall carbon nanotube (SWCNT) species were established under second-order optical transition excitation. The results demonstrate a significantly under-recognized complexity in the evaluation of Raman spectra for the assignment of (n,m) population distributions. The strong chiral angle and mod dependencies affect the intensity ratio of RBM to G band and can result in misleading interpretations. Additionally, we validate our results on chirality dependent G+ and G- positions, supporting accuracy in literature values for these peak positions and further extend the trend to the small diameter regime by including the first (5,4) second-order resonance Raman spectra. Together, the Raman spectra library is demonstrated to be sufficient for decoupling multiple species via a spectral fitting process, to enable fundamental characterization even in mixed chiral population samples.
Resonance Raman, carbon nanotubes, Raman Intensity Ratio