Adiabatic release measurements in α-quartz between 300 and 1200 GPa: Characterization of α-quartz as a shock standard in the multimegabar regime
Adiabatic release measurements in α-quartz between 300 and 1200 GPa: Characterization of α-quartz as a shock standard in the multimegabar regime
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DOI：
10.1103/physrevb.88.184107
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发表时间：
2013-11-25
影响因子：
3.7
通讯作者：
Desjarlais, M. P.
中科院分区：
文献类型：
--
作者：
Knudson, M. D.;Desjarlais, M. P.
近年来，α-石英已被大量地用作多兆巴范围（1 Mbar = 100 GPa）中的阻抗匹配标准。这是由于这样一个事实，即上面类似于90-100 GPa沿着主要Hugoniot α-石英变得反射，因此冲击速度可以测量到高精度使用速度干涉。该特性允许高精度测量，然而，阻抗匹配测量的准确性取决于对Hugoniot和α-石英的释放或再震响应的了解。在这里，我们提出了几个绝热释放测量的结果，从类似的300-1200 GPa状态沿着主要Hugoniot使用全密度聚甲基戊烯（通常称为TPX），和类似于190和类似于110毫克/立方厘米的二氧化硅气凝胶标准。这些数据进行了分析的框架内的一个简单的，分析模型的动机是由第一性原理的分子动力学调查到释放响应的α-石英。结合，这种理论和实验研究提供了一种方法来执行阻抗匹配计算，而不需要呼吁任何表格状态方程的α-石英。作为一个分析模型，该方法允许传播所有的不确定性，包括随机测量不确定性和系统的Hugoniot和释放响应的α-石英的不确定性。这项工作建立了α-石英作为一个高精度的标准，在多兆巴政权的阻抗匹配。我们还注意到，实验验证的模型框架应被证明是有用的，在广泛的状态方程二氧化硅，在地壳和地幔的主要组成部分的发展。这种模型对于准确模拟高速巨型撞击至关重要，这种撞击被认为是类地行星形成最后阶段的普遍现象。
a-quartz has been used prolifically in recent years as an impedance matching standard in the multimegabar regime (1 Mbar = 100 GPa). This is due to the fact that above similar to 90-100 GPa along the principal Hugoniot alpha-quartz becomes reflective, and thus shock velocities can be measured to high precision using velocity interferometry. This property allows for high-precision measurements, however, the accuracy of impedance matching measurements depends upon the knowledge of both the Hugoniot and the release or reshock response of alpha-quartz. Here, we present the results of several adiabatic release measurements of alpha-quartz from similar to 300-1200 GPa states along the principal Hugoniot using full density polymethylpentene (commonly known as TPX), and both similar to 190 and similar to 110 mg/cc silica aerogel standards. These data were analyzed within the framework of a simple, analytical model that was motivated by a first-principles molecular dynamics investigation into the release response of alpha-quartz. Combined, this theoretical and experimental study provides a method to perform impedance matching calculations without the need to appeal to any tabular equation of state for alpha-quartz. As an analytical model, this method allows for propagation of all uncertainty, including the random measurement uncertainties and the systematic uncertainties of the Hugoniot and release response of alpha-quartz. This work establishes alpha-quartz for use as a high-precision standard for impedance matching in the multimegabar regime. We also note that the experimentally validated model framework should prove to be useful in the development of wide range equations of state for silica, a major constituent in the Earth's crust and mantle. Such models are crucial for accurate simulations of high-velocity giant impacts that are thought to be prevalent in the final stages of terrestrial planet formation.