HELMHOLTZ FREE-ENERGY AND THERMODYNAMICS OF SHOCK-COMPRESSED SOLIDS

A new general procedure for constructing Helmholtz thermodynamic poten tials (free energies) of solids within the quasi-harmonic approximatio n is devised. A Helmholtz free energy is expressed as an explicit anal ytical function of volume and temperature. Using cesium iodide as an e xample, it is shown that the proposed expression for the free energy a llows us to. calculate thermodynamic parameters of materials (compress ibility, heat capacity, coefficient of thermal expansion, etc.) under static conditions and in shock waves over the pressure range from zero to hundreds of gigapascals at temperatures from room temperature to s everal thousands degrees.