An Equation of State of Corundum Based on Planck–Einstein Functions

Abstract

The possibility of constructing the equation of state of a crystalline substance based on a linear combination of the Planck–Einstein functions is shown using the example of corundum α-Al2O3. Two versions of the corundum equation of state are obtained on the basis of functions F(V,T) and G(P,T) as a result of the self-consistency of the heat capacity values, the enthalpy increment, PVT data, the coefficient of thermal expansion, and the adiabatic modulus of elasticity. Both equations provide an acceptable description of the above properties in a wide range of variables (up to a pressure of 165 GPa and a temperature of 2250 K).