Unified analyses for P-V-T equation of state of MgO: A solution for pressure-scale problems in high P-T experiments
Unified analyses for P-V-T equation of state of MgO: A solution for pressure-scale problems in high P-T experiments
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DOI：
10.1029/2008jb005813
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发表时间：
2009-03-20
影响因子：
3.9
通讯作者：
Tsuchiya, Taku
中科院分区：
文献类型：
--
作者：
Tange, Yoshinori;Nishihara, Yu;Tsuchiya, Taku
为了确定准确可靠的MgO高温高压状态方程，对1atm ~ 196 GPa、300-3700 K范围内的各种压力无标度实验数据集进行了统一分析，包括零压热膨胀数据、零压高温绝热体积模量（K-S）数据、室温和高压KS数据，以及冲击压缩数据。在对几种基于Mie-Gruneisen-Debye方程的300 K等温压缩的Vinet方程和三阶Birch-Murnaghan方程的热力学模型进行测试后，我们用一种新的函数形式gamma = gamma（0）{1 + a[（V/V-0）（B）-1]}来表示Gruneisen参数的体积依赖性，从而确定了K '（T0）和gamma（V）。通过最小二乘法分析，在V-0、K-S_0、α（0）和C-P_0的零压和室温特性的前提下，同时优化了代表P-V-T状态方程所需的一组参数K '（T_0）、γ（0）、α和B。在不确定度范围内，新的MgO物态方程模型成功地再现了196 GPa和3700 K范围内的所有P-V-T-K-S数据，计算压力与实测压力的总残差为0.8 GPa。这些EOS模型虽然非常简单，但能够在很宽的压力-温度范围内相当准确地再现现有数据，并且完全独立于其他压力尺度。我们提出了这些模型适用于定量高压和高温实验的主要压力校准标准。
In order to determine an accurate and reliable high-pressure and high-temperature equation of state (EOS) of MgO, unified analyses were carried out for various pressure-scale-free experimental data sets measured at 1 atm to 196 GPa and 300-3700 K, which are zero-pressure thermal expansion data, zero-pressure and high-temperature adiabatic bulk modulus (K-S) data, room temperature and high-pressure KS data, and shock compression data. After testing several EOS models based on the Mie-Gruneisen-Debye description for the thermal pressures with the Vinet and the third-order Birch-Murnaghan equations for the 300-K isothermal compression, we determined the K'(T0) and gamma(V) using a new functional form gamma = gamma(0){1 + a[(V/V-0)(b)-1]} to express the volume dependence of the Gruneisen parameter. Through least squares analyses with prerequisite zero-pressure and room temperature properties of V-0, K-S0, alpha(0), and C-P0, we simultaneously optimized a set of parameters of K'(T0), gamma(0), alpha, and b required to represent the P-V-T EOS. Determined new EOS models of MgO successfully reproduced all the analyzed P-V-T-K-S data up to 196 GPa and 3700 K within the uncertainties, and the total residuals between calculated and observed pressures were found to be 0.8 GPa in root mean squares. These EOS models, even though very simple, are able to reproduce available data quite accurately in the wide pressure-temperature range and completely independent from other pressure scales. We propose these models for primary pressure calibration standards applicable to quantitative high-pressure and high-temperature experiments.