含Fe2 +桥镁石的热弹性
Thermoelasticity of Fe2+-bearing bridgmanite
摘要：
本文采用LDA+U方法计算了成分为（$_{(1-x)}$）$_3$的硼镁石的高温弹性性质。镁端构件（x=0）的弹性模量和声速的结果与最新的高压和高温实验测量结果非常吻合。在含铁系统中，我们特别关注的热弹性参数的变化，发生在亚铁的状态变化以上$\sim$ 30 GPa，通常归因于高自旋（HS）到中间自旋（IS）的交叉，但解释的第一性原理计算作为替代铁在钙钛矿笼的横向位移。我们表明，这种变化的测量效果的状态方程的这个系统可以解释由替代铁的横向位移，而不是由HS到IS交叉。计算的弹性性质的（Mg $_{0.875}$ Fe $_{0.125}^{2+}$）SiO $_3$沿绝热地幔地热，有点高估纵向速度，但产生的密度和剪切速度完全一致的初步参考地球模型数据在整个大部分的下地幔。
英文摘要：
We present LDA+U calculations of high temperature elastic properties of bridgmanite with composition (Mg$_{(1-x)}$Fe$_{x}^{2+}$)SiO$_3$ for $0\le{x}\le0.125$. Results of elastic moduli and acoustic velocities for the Mg-end member (x=0) agree very well with the latest high pressure and high temperature experimental measurements. In the iron-bearing system, we focus particularly on the change in thermoelastic parameters across the state change that occurs in ferrous iron above $\sim$30 GPa, often attributed to a high-spin (HS) to intermediate spin (IS) crossover but explained by first principles calculations as a lateral displacement of substitutional iron in the perovskite cage. We show that the measured effect of this change on the equation of state of this system can be explained by the lateral displacement of substitutional iron, not by the HS to IS crossover. The calculated elastic properties of (Mg$_{0.875}$Fe$_{0.125}^{2+}$)SiO$_3$ along an adiabatic mantle geotherm, somewhat overestimate longitudinal velocities but produce densities and shear velocities quite consistent with Preliminary Reference Earth Model data throughout most of the lower mantle.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
