EAPSI: Evaluating the Melting and Vibrational Properties of Phase H as a Function of Pressure

EAPSI：评估 H 相的熔融和振动特性与压力的函数关系

• 批准号: 1612833
• 负责人: Elizabeth Thompson
• 金额: $ 0.04万
• 依托单位: Thompson Elizabeth C
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1612833&HistoricalAwards=false
• 关键词: EAPSI; Evaluating; Melting; Vibrational; Properties

Forty years of scientific literature on the topic has produced wildly variable estimates of the water content within the deep Earth--with values ranging from a quarter to four times the volume of water found in Earth's oceans. The recent discovery of hydrous 'phase H' (MgSiO4H2) provides a new insight into the distribution of water in the Earth's interior. Determining the stability of hydrous phases such as phase H aids in constraining the quantity of water in the lower mantle, a region of the Earth almost 100 times more massive than the crust. The formation of phase H was first predicted in a computational study by Dr. Jun Tsuchiya of the Geodynamics Research Center (GRC) at the University of Ehime, Japan. Dr. Tsuchiya will lend her expertise using first-principles techniques to study high-pressure hydrous phases to this project and the GRC will provide use of a supercomputer that will enable the timely completion of this project.This proposal aims to provide critical insight into the deep Earth's hydrogen budget via three ab initio investigations into key hydrous mantle phases: (1) modeling the melting behavior of phase H as a function of pressure, (2) modeling the melting curve of d-AlOOH, and (3) first-principles calculations of the vibrational properties of phase H as a function of pressure. The melting curves of phase H and d-AlOOH will be determined using a first principles molecular dynamics technique. This type of calculation enables the determination of thermodynamic properties by numerically modeling the interatomic potentials between particles in the system of interest. Vibrational properties of phase H will be calculated using first-principles calculations based on a generalized gradient approximation to the exchange-correlation functional. These calculations are complementary to the principal investigator?s experimental efforts to investigate hydrous phases under extreme conditions and will help constrain the water budget of the Earth's deep interior.This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Japan Society for the Promotion of Science.

关于该主题的四十年的科学文献已经产生了深层地球内水含量的巨大估计，其值是地球海洋中水量的四分之一到四倍。最近发现的含水“相H”（MGSIO4H2）为水在地球内部的分布提供了新的见解。确定液压相（例如H期）的稳定性有助于约束下地幔中的水数，地球的一个区域几乎是地壳的巨大尺寸的近100倍。 H阶段H的形成首先是在日本Ehime大学地球动力学研究中心（GRC）的Jun Tsuchiya博士的一项计算研究中预测的。 Tsuchiya博士将使用第一原告技术借用她的专业知识来研究该项目的高压含水阶段，而GRC将提供超级计算机的使用，这将使该项目及时完成该项目。该提案旨在通过对键入的液压措施进行三个阶段的压力（2）旋转的压力（1）旋转（1）模型（1）（1）模型（1），该提案旨在对深地球预算进行对深度预算的研究（1）旋转：1）（1）（1）（1）（1）旋转型号（1）（1）（1）（1）（1）（1）模型（1）（1））（1）（1）（1）模型（1））（1）（1））（1）（1））（1）（1））（1））（1））（1）（1））（1））（1））（1））（1））（1））对D-Alooh的熔融曲线进行建模，（3）相H的振动特性的第一原理计算是压力的函数。相H和D-alooh相的熔融曲线将使用第一原理分子动力学技术确定。这种类型的计算可以通过对感兴趣系统中粒子之间的原子间电位进行数值建模，从而确定热力学特性。相H的振动特性将使用基于对交换相关功能的广义梯度近似的第一原理计算计算。这些计算是对主要研究者在极端条件下研究含水阶段的实验努力的补充，并将有助于限制地球深处的水预算。根据东亚和太平洋夏季研究所计划的奖项支持美国研究生的夏季研究，并由NSF和NSF和日本促进科学促进社会共同资助。