Vibrational and thermal properties of pressure polymerized C60

The kinetics of C-60 polymerization were studied in the temperature range 450-500 K at pressures below 1 GPa by measurements of the time dependence of the thermal conductivity. The vibrational spectrum of polymerized C-60 was studied by inelastic neutron scattering. We find drastic changes in the spectrum compared with the vibrational spectrum of pristine C-60: hardening of intermolecular modes, appearance of a new broad vibrational band at low energies, splitting and significant changes in the peak positions of intramolecular modes. The thermal conductivity, lambda of polymerized C-60 was measured in the temperature range 150-320 K and was found to increase with rising temperature, that reflects strong phonon scattering. The presence of polymeric chains of different length and a high degree of structural disorder in the crystalline lattice of the polymeric phase are the most probable factors responsible for the glass-like behaviour of lambda(T).