Abstract

This work introduces an elegant new version of the exponential equation of state (EOS) that can be applied in different orders, from first to fourth, for improved prediction accuracy across different levels of material compression. This new exponential EOS is particularly important for predicting material behaviour under pressure; in high-pressure physics, it is of paramount importance. A comprehensive and close comparison of this exponential EOS to the well-documented fourth-order Birch-Murnaghan EOS has been conducted. The comparison indicates that the exponential EOS matches, and even beats, the BirchMurnaghan one more often at high compression levels. Now, this is especially useful because the fourth-order exponential EOS shows much accuracy for materials such as hexagonal close-packed (HCP) iron and sodium halides under high compression. In comparison, although the Birch-Murnaghan EOS is relatively consistent with respect to the data that are obtained at lower compressive settings, it begins to deviate from the data obtained with increasing compressive conditions. Besides, the report reviews the Shanker EOS. It contains a citation to the work of M. Kumar and others, who described its limitations at high compression and suggested adjustments (parameter-wise) for a range of materials. Thus, to get an accurate result on both low and high-compression settings the new fourth-order exponential EOS has been proposed which is also more versatile and provides consistent and reliable results and is the new powerful technique in high-pressure physics.

Keywords

equation of state, carbon nanotubes, compression, thermal pressure, murnaghan eos, kholiya eos, usual-tait eos