Thermodynamic formulation of enthalpy-based equation of state for condensed substances

摘要

Thermodynamic formulation has been made for the enthalpy-pressure-volume equation of state for condensed substances based on the assumptions proposed by Rice and Walsh in 1957. We found a thermodynamic constraint that must be imposed on the specific heat at constant pressure and a material parameter defined by them and later in another form by Wu and Jing. Behavior of this material parameter has been calculated based on the calculation of the Grüneisen parameter. Comparison of this material parameter along shock Hugoniot and an isentrope revealed that this parameter depends on entropy as well as pressure, but entropy dependence is very small. This result strongly suggests that this parameter as a function of only pressure will give sufficient description of high-pressure behavior of solid materials within appropriate range of pressure.