Temperature effects on a new equation of state of solids

Recently we have proposed an isothermal equation of state of solids, and applied it to a variety of substances to show that it agrees with the isothermal pressure-volume data quite accurately up to ultrahigh pressures, and that its agreement with data is superior to the existing equations of state. Further, it has been shown that the bulk modulus and its first pressure derivative, extracted by it, are in excellent agreement with experiment. In the present study, temperature effect is added on this new equation of state, following a widely used approach involving the input of zero-pressure bulk moduli parameters and thermal expansion, all evaluated at a single reference temperature. The resultant temperature-dependent equation of state is applied to predict the isotherms over a wide range of temperature, the thermal expansion as a function of temperature, and the temperature dependence of the isothermal bulk modulus and its pressure derivative. These predictions are tested using literature data for four solids: sodium chloride, gold, molybdenum and tungsten. Good agreement is obtained between theory and data. Furthermore, the predictions are compared with those obtained from a similar temperature-dependent equation of state recently proposed, and the superior prediction capability of our model, in the P-V-T space, is demonstrated.