VIBRATIONAL-MODES OF CARBON NANOTUBES - SPECTROSCOPY AND THEORY

Experimental and theoretical studies of the vibrational modes of carbo n nanotubes are reviewed. The closing of a 2D graphene sheet into a tu bule is found to lead to several new infrared (IR)- and Raman-active m odes. The number of these modes is found to depend on the tubule symme try and not on the diameter. Their diameter-dependent frequencies are calculated using a zone-folding model. Results of Raman scattering stu dies on are-derived carbons containing nested or single-wall nanotubes are discussed. They are compared to theory and to that observed for o ther sp(2) carbons also present in the sample.