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arXiv · 0708.0183

First-principles thermal equation of state and thermoelasticity for hcp Fe under high pressures

Xianwei Sha·R. E. Cohen
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Abstract

We investigate the equation of state and elastic properties of nonmagnetic hcp iron at high pressures and high temperatures using the first principles linear response linear-muffin-tin-orbital method in the generalized-gradient approximation. We calculate the Helmholtz free energy as a function of volume, temperature, and volume-constrained strain, including the electronic excitation contributions from band structures and lattice vibrational contributions from quasi-harmonic lattice dynamics. We perform detailed investigations on the behavior of elastic moduli and equation of state properties as a function of temperature and pressure, including the pressure-volume equation of state, bulk modulus, the thermal expansion coefficient, the Gruneisen ratio, and the shock Hugoniots. A detailed comparison has been made with available experimental measurements and theoretical predictions.

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Xianwei Sha, R. E. Cohen. 2007-08-01. First-principles thermal equation of state and thermoelasticity for hcp Fe under high pressures. https://arxiv.org/abs/0708.0183

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