THERMODYNAMIC QUANTITIES AT HIGH PRESSURES IN THE i AND θ PHASES OF SOLID NITROGEN DEDUCED BY RAMAN FREQUENCY SHIFTS FOR THE INTERNAL MODES IN LITERATURE

Abstract

The pressure dependence of the Raman frequencies of the internal modes is analyzed (T = 300 K ) for the phases i and θ of solid nitrogen using the experimental data from the literature. Through the mode Grüneisen parameter, the isothermal compressibility κT, thermal expansion αp and the specific heat Cp–Cv are calculated as a function of pressure using the Raman data in these phases. We obtain that the αp varies linearly with the (1/υ)(∂υ/∂P)T and also that the Cp–Cv varies linearly with the αp for N 2. Our results show that by means of the analysis given here, the αp, κT and Cp–Cv can be predicted from the Raman frequency shifts for the i and θ phases of solid nitrogen.