Equation of state and internally consistent thermodynamic functions of minerals

We present a modified equation of state for solid phases based on the metho d of potentials of Zharkov and Kalinin (1968). The potential part of the He lmholtz free energy was expressed in a logarithmic form (Poirier and Tarant ola. 1998), and a three-parameter modification of the Bose-Einstein model ( Kut' in and Pyadushkin, 1998) was used instead of the Debye energy. This al lowed us to approximate with high accuracy the experimental measurements of heat capacity, enthalpy, volume, and adiabatic bulk modulus between 10-15 K and the melting temperature at zero pressure and volume data in the regio n of its experimental determination using a single equation of state. Takin g sodium chloride as an example, it was shown that the proposed thermal equ ation of state allowed us to evaluate self-consistent thermodynamic functio ns from experimental measurements, as well as to calculate these functions in a wide range of T, P, and V.