On the isobaric volume dependence of the ratio between volume thermal expansivity and specific heat (αV/CP)

Abstract

A thermodynamic analysis of the temperature sensitivity of the ratio (λ) between volume thermal expansivity (αV) and isobaric specific heat (CP) is presented. By invoking the temperature independence of the thermal Grüneisen parameter (γG), some simple approximations are derived for the isobaric volume dependence of the ratio αV/CP. In addition, the temperature dependence of γG has also been investigated under the condition that there exists a linear scaling relation between bulk modulus (BS) and enthalpy increment (ΔH). The relations suggested in this study form a consistent thermodynamic framework that serves to relate thermal and elastic properties on a general system-independent basis. As an illustrative application, the isobaric volume dependence of αV/CP has been estimated for MgO and the results are found to be in good agreement with experiment.