Use of Critically Evaluated Data on Copper to Test the Mie-Grüneisen Equation of State

Abstract

Thermal expansion data that is now available for copper is believed to be accurate within the range 0–1000 K. Using this data and other critically evaluated data on thermodynamics and elastic properties various approximations of the Mie-Grüneisen equation of state PV=−V[∂φ(V)/∂V]+γEhave been evaluated. These approximations, assuming zero pressure, are usually written as (V−V0V0)=(K0γ0/V0)E1−A(K0γ0/V0)E,[(V−V0)/V0]−A[(V−V0)V0]2=(K0γ0/V0)E. Both of these approximations fail to provide a reasonable fit to the data, especially in the low-temperature region. If, contrary to the normal usage of these approximations, the Grüneisen parameter is allowed to be temperature dependent then a better fit, both qualitative and quantitative, to the data is obtained, [(V−V0)/V0]−A[(V−V0)/V0]2=(K0/V0)γE. This form of the Mie-Grüneisen equation also provides a means of estimating the temperature dependence of the Grüneisen parameter when compressibility data is only available at room temperature γ=a(V−V0)/V0E[1−b(V−V0V0)].