Thermodynamics property study of Re by the first-principle

Within the framework of the quasiharmonic Debye-Grüneisen approximation, the equation of state and thermodynamics properties, including bulk modulus, Gibbs free energy, enthalpy, entropy, heat capacity and volume thermal expansion coefficient of Re have been studied using the first-principles projector-augmented wave method. The results reveal that the pressure-volume curve from the eight-order Birch-Murnaghan is in good agreement with the experimental measurements. Gibbs free energy, enthalpy, entropy, heat capacity and volume thermal expansion coefficient of Re at 0 GPa as a function of temperature are consistent well with the experimental data. At 0, 50, 100, 150 and 200 GPa, bulk modulus and Gibbs free energy decrease with the increasing of temperature, but enthalpy and entropy increase. As the temperature increases, the electronic heat capacity increases linearly, but the vibrational heat capacity increases following T3 law at low temperature and it nearly approaches to the Dulong-Petit result 3nNAkB at high temperature. The estimated Debye temperature of Re from heat capacity at constant volume is 430 K that is in agreement with the available measurements. Copyright © 2013 Northwest Institute for Nonferrous Metal Research. Published by Elsevier BV. All rights reserved.