Grüneisen Parameter along Hugoniot and Melting Temperature of ε-Iron: a Result from Thermodynamic Calculations

Based on the available data of specific heat C_v at constant volume and the Grüneisen parameter γ of both lattice and electron contributions, we present a consistent method for simultaneously calculating the effective or synthesized Grüneisen parameter along Hugoniot, γ_eH, covering solid, mixed, and liquid states, and the melting temperature T_m for ε-iron. The rationality validation for this method is confirmed as compared with the experimental data, including the measured T_m and Hugoniot bulk sound velocities C_b. The calculated γ_eH and T_m for ε-iron at the Earth’s inner-core boundary (330GPa) are 1.58 and 5930K, respectively, which are close to the values of 1.53 and 6050K given by Anderson J. Phys. Chem. Solids 64 (2003) 2125. This method for determination of γ_eH could be, in principle, also applicable to any thermodynamic state calculations, e.g., along isothermal and isentropic paths, other than the Hugoniot locus.