Calculation of the thermodynamic quantities from the Raman frequency shifts and the Pippard relations for the alpha, -alpha and alpha ' phases of oxygen

Abstract

Thermodynamic quantities such as the isothermal compressibility, thermal expansion and the difference in the specific heat are calculated as a function of pressure (T=10 K) for the alpha,-alpha and alpha ' phases of oxygen using the observed Raman frequencies of the two librons and one vibron from the literature through the mode Gruneisen parameter for this molecular solid. Calculated thermodynamic quantities decrease with increasing pressure with some discrepancies due to the different pressure - induced Raman frequency shifts of these modes studied for the alpha, -alpha and alpha ' phases of O-2. A linear variation of the difference in the specific heat with the thermal expansion and also a linear variation of the thermal expansion with the isothermal compressibility (Pippard relations) are obtained for the alpha, -alpha and alpha ' phases of oxygen as studied here. Calculated isothermal compressibility, thermal expansion and the difference in the specific heat with the Pippard relations which we obtained here at various pressures (T= 10K), can be examined with the experimental measurements for the alpha, -alpha and alpha ' phases of oxygen molecule.