In Jiang et al, 2002, we can find a "strong enhancement of the Breit-Wigner-Fano Raman line in carbon nanotube bundles caused by plasmon band formation". The three main features in Raman spectra of nanotubes are the RBM, the mode of disordered carbon (D line) and the G lines, originated by the tangential vibrations of the carbon atoms. "For metallic SWCNTs an additional band close to the doublet of G lines (~1550 cm -1 ) can be observed, which can be well fitted by a BWF line shape. This band results from coupling of phonons to the electronic continuum of the metallic tubes and is commonly used to distinguish between metallic and semiconducting SWCNTs. Regarding the plasmons, see also Appendix A.