Low energy excitations in fullerene dimers and in single wall carbon nanotubes

Low energy vibrational excitations in single bonded fullerene dimeres (C59N)(2) and (C-60(-))(2) and in single wall carbon nanotubes were investigated by Raman spectroscopy. The two isoelectronic and isostructural dimeres exhibited very similar spectra with strongly resonance enhanced lines for the radial modes if excitation was with a red laser. For the biazafullerene for the first time all three geometrically allowed intercage modes could be identified. For the single wall carbon nanotubes the response from the radial breathing mode was analyzed for excitation with 20 different laser lines. The results were found to be consistent with contributions from all geometrically allowed tubes and a strong contribution to the force constant from intercage interaction.