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

The linear orthorhombic polymer of C60 (e) has 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 (a). 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 to a metastable highly disordered phase (b), 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 is metastable and transforms to a mixture of pristine and dimerized C60 within ∼30 h (c) and (d).