Pressure-induced transformations in the linear orthorhombic polymeric phase of C60

The pressure-induced transformations in the linear orthorhombic polymer of C60 have been studied by in situ Raman scattering. The simultaneous application of pressure and laser irradiation results in fast photo-transformation of the 1D-O polymer at pressures as low as ∼0.3 GPa. The pressure dependence of the Raman modes of the photo-transformed polymer shows singularities near ∼4 GPa and ∼15 GPa, related to reversible phase transition and transformation to a metastable highly disordered phase, respectively. The diffuse spectrum of the disordered phase does not exhibit essential changes for increasing pressure up to 29 GPa. The recovered high-pressure phase transforms to a mixture of pristine and dimerized C60 within ∼30 h.