A New Approach to Evaluate Pressure of Solids at High Compression

Abstract

The new isothermal equation of state (NEOS) for solids is derived through the theory of lattice potential, utilizing the concept of volume dependence of the short-range force constant. To obtain this equation of state, we employed the concept of the third-order approximation of the lattice potential. For critical analysis, we compared the results of isothermal equations of state (EOSs), such as Vinet EOS, Murnaghan EOS, Holzapfel EOS, Born-Mie EOS, Birch–Murnaghan EOS, and NEOS. The newly derived equation of state (NEOS) has been utilized to analyze the compression behavior of molybdenum (Mo), Potassium (K), and Xenon (Xe). It was found that NEOS is in good agreement with experimental data for given solids Mo, K, and Xe up to high compression, while Vinet EOS, Murnaghan EOS, Born-Mie EOS, Holzapfel EOS, and Birch–Murnaghan EOS are less sensitive in calculating pressure at high compression in most cases. Thus, NEOS remains consistent and in good agreement with experimental results for all the samples of solids taken, even up to high compression.