Abstract
The aim of the present paper is to identify the main infrared vibrational features of carbon nanotubes. In this goal, infrared experiments have been performed on different well-characterized single-walled carbon nanotubes (SWCNTs) and double-walled carbon nanotubes (DWCNTs) as well as graphite and carbon aerogel. The comparison between the experimental spectra measured on these different samples allows us to identify the infrared-active modes of carbon nanotubes. In SWCNTs, the tangential modes are located around 1590 cm−1 and the radial mode around 860 cm−1. This latter mode vanishes in the infrared spectrum of DWCNTs. Finally, in the infrared spectra of all the carbon nanotubes investigated, a band around 1200 cm−1 is evidenced and assigned to the D-band (disorder-induced band).