Energy spectra and phase transitions in fullerite C70 crystals under high pressure

The spectra of the light combination scattering, optical absorption and luminescence of monocrystals and fullerite C70 at the temperature of approximately 300 K and under pressure up to 126 Pa are measured. The dω/dP baric shift and Grueneisen active parameters by the combination scattering of intermolecular modes are determined. It is established that under pressures P1 approximately 2 GPa and P2 approximately 5.5 GPa the dω/dP value for some phonon modes is changed as the half-width of lines of the combination scattering. These peculiarities in the combination scattering spectra are related to the phase transitions under high pressure