Quantum Mechanical Modeling of Major Mantle Materials

在过去的十年里，计算矿物物理学在我们对地球的理解中发挥了重要作用。它通过扩大热力学条件的范围来补充实验，材料性质可以被研究，并提供了基于原子尺度的地球内部性质的新见解。该项目支持继续使用第一性原理计算来量化地球内部深处一些常见矿物的基本化学和物理特性的研究。根据这项拨款，拟扩大地球材料的第一性原理研究，以i)包括使用该小组最近开发的方法计算矿物的热性质和相关系的非调和效应；Ii)推进固溶体相变的研究，特别是钙钛矿后相变；Iii)探讨下地幔中第二重要的阶段铁方长石的自旋态交叉的流变学后果；Iv)将这些研究与地幔的地球动力学模拟相结合。这些研究将对我们的理解做出关键贡献：1)多相聚合体的热力学平衡；Ii)主要地幔矿物的热力学相界性质。在不同的系统中，克拉珀龙斜率、不连续面和两相环的测量仍然存在很大的不确定性。这些量控制着地幔动力学，并将得到更好的约束；Iii)铁方长石的流变学已经涉及到所建议的粘度最小值约1,600公里深，现在将进行研究；Iv)对这些结果的地球动力学敏感性及其后果。该研究将揭示D”和中-下地幔区域的性质和动力学，具有内在的跨学科价值。

In the last decade, computational mineral physics has played a fundamental role in our understanding of the Earth. It has complemented experiments by expanding the range of thermodynamics conditions materials properties can be investigated and has provided new insights into the nature of Earth's interior based on atomic scale arguments. This project supports a continuation of studies that use first principles calculations to quantify fundamental chemical and physical properties of some common minerals present deep in the interior of the Earth.Under this grant it is proposed to expand first principles studies of Earth's materials to i) include anharmonic effects on calculations of thermal properties and phase relations of minerals using methods recently developed by the team; ii) advance studies of phase transformations in solid solutions, particularly for the post-perovskite transition; iii) explore the rheological consequences of the spin-state crossover in ferropericlase, the second most important phase in the lower mantle; iv) couple these studies with geodynamical modeling of the mantle. These studies will make key contributions to our understanding of i) thermodynamic equilibrium in multi-phase aggregates; ii) properties of thermodynamics phase boundaries of major mantle minerals. There are still large uncertainties associated with measurements of Clapeyron slopes, discontinuities, and two-phase loops in divariant systems. These quantities control mantle dynamics and will be better constrained; iii) the rheology of ferropericlase has been implicated in the proposed viscosity minimum around 1,600 km depth and will now be investigated; iv) the geodynamical sensitivity to and consequences of these results. This research, which has intrinsic interdisciplinary value, will shed light on the nature and dynamics in the D" and mid-lower mantle regions.