The vibrational spectra of insulating pressure polymerised C 60 and conducting o -RbC 60 polymers are studied by Raman and neutron spectroscopy. Model calculations give detailed informations on particular excitations and restoring forces as well. A pronounced anomalous phonon softening present in the conducting polymer is not found in the neutral compound. The breaking up of polymer chains in pressure polymerized C 60 is followed with temperature.
