The influence of O2 on the phase transition of C60 crystal Original Research Article

The order–disorder phase transition temperature of the C60 crystal intercalated with O2 shifts from 257 (of pure sample) to 236 K. The internal friction peak due to the orientational relaxation also shifts from 142.8 (of pure sample) to 137.2 K and takes an asymmetric shape. The activation energy varies from 252 (of pure sample) to 226 meV. It is proposed that non-sphericity of O2 influences the phase transition temperature and the orientational relaxation dramatically.