The phonon spectrum of highly oriented pyrolitic graphite and of single wall carbon nanotubes was studied with inelastic electron tunneling spectroscopy using a low temperature scanning tunneling microscope.  The measured inelastic spectrum of graphite is found to be directly proportional to the calculated vibrational density of states.  Based on the electronic band structure of graphite we suggest that a phonon-assisted tunneling process influences the amplitude of the observed inelastic spectrum. [1].  Similarly the phonon spectrum of single wall carbon nanotubes adsorbed on Au substrates was measured.  On the low energy part of the spectrum the radial breathing mode (RBM) has been identified and its linear dependence on the inverse of the tube diameter demonstrated.  Furthermore, based on the high spacial resolution typical of the scanning tunneling technique, the behavior of the radial mode becomes accessible in close proximity to topological defects, like intermolecular junctions, tube endings [2], or crossed junctions of tubes where the tube cage is sensitively deformed.    

[1] L.Vitali et al,  Physical Review B.69.121414R (2004)
[2] L.Vitali et al,  Physical Review Letters 93.136103.(2004)