Adiabatic, Isothermal, and Intermediate Pressure Derivatives of the Elastic Constants for Cubic Symmetry. I. Basic Formulae

Abstract The thermodynamic relations between the adiabatic pressure derivatives of the adiabatic elastic constants, the isothermal pressure derivatives of the isothermal elastic constants, and the isothermal pressure derivatives of the adiabatic elastic constants that can be measured ultrasonically are compiled and correctly proved for cubic symmetry. Also, the corresponding relations between the linear combinations of the third‐order elastic constants that can be determined from these pressure coefficients are derived.