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中国物理学会期刊

金属铅的宽区多相物态方程

CSTR: 32037.14.aps.74.20250569

A wide-range multiphase equation of state for lead

CSTR: 32037.14.aps.74.20250569
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  • 本文从Helmholtz自由能出发构建了铅的宽区多相物态方程, 覆盖从常温到10 MK、从常压到107 GPa的温压范围, 计算了冲击雨贡纽线、300 K等温线、熔化线及温稠密过渡区热力学物性, 并与实验值、铅已有的宽区物态方程数据库SESAME-3200以及第一性原理模拟结果进行了对比分析. 一方面, 本文的模型能较好地再现各类实验数据; 另一方面, 在温稠密过渡区, 本文的模型获得了扩展的第一性原理分子动力学模拟结果的验证, 相比SESAME-3200更符合第一性原理的模拟结果. 本文数据集可在https://www.doi.org/10.57760/sciencedb.j00213.00166中访问获取.

     

    We present a multi-phase equation of state (EOS) for lead (Pb, Z = 82) in wide ranges of densities and temperatures: 11.34\;\textg/\textc\textm^3 < \rho < 80\; \textg/\textc\textm^3, 300\;\mathrmK < T < 10\;\mathrmMK. The EOS model is based on a standard decomposition of the Helmholtz free energy that is regarded as a function of the specific volume and the temperature into cold term, ion-thermal term, and electronic excitation term. The cold term models both the compression and the expansion states; the ion-thermal term introduces the Debye approximation and the melting entropy; the electronic excitation term employs the Thomas-Fermi-Kirzhnits (TFK) model. The thermodynamic properties of the warm-dense lead are calculated using the extended first-principles molecular dynamics (ext-FPMD) method, with the density reaching five times that of ambient density and the temperature up to 0.4 MK. Our EOS model is used to predict the principle Hugoniot, the room-temperature isotherm, the melting curve, and the thermodynamic properties in the warm-dense region. A systematic comparison with the experimental data, the SESAME-3200 table, and the ext-FPMD calculations is made and shows that our EOS model is consistent with not only the various experimental data, but also the ext-FPMD calculations, indicating some superiority over the SESAME-3200 table in the warm-dense region. The datasets presented in this paper, including the tabular EOS consisting of internal energy and pressure at the different densities and temperatures, are openly available at https://www.doi.org/10.57760/sciencedb.j00213.00166.

     

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