Collaborative Research: First Principles Investigation of Silicate Liquids at Mantle Conditions

合作研究：地幔条件下硅酸盐液体的第一原理研究

• 批准号: 0409121
• 负责人: Lars Stixrude
• 金额: $ 19.8万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0409121&HistoricalAwards=false
• 关键词: Collaborative; Research; First; Principles; Investigation

The project will apply the first-principles approach based on density functional theory (DFT) to investigate the physico-chemical properties of silicate liquids, which are major components of the Earth's mantle. The approach has already been proven to be an ideal complement to the experimental approach in studying a wide range of crystalline properties of the Earth materials and here it will be extended to simulation of material systems involving relative large number of atoms. These large-scale simulations will result in major advances in our knowledge of silicate liquids over the large range of pressure, temperature, and composition that are crucial for a better understanding of planetary evolution, as silicate liquids are primary means of heat and mass transport inside the Earth. The project will make key contributions to understanding of: a) Buoyancy of silicate liquids through ab initio predictions of the equation of state including liquids of diopside, enstatite, and forsterite compositions over the pressure-temperature regime of the mantle; b) Structure of silicate liquids via analysis of the complete structural information that is available in theoretical simulations including coordination numbers, bond lengths, and bond angles. Analysis of the structure of liquids of diopside and hydrous albite composition, and melts on the MgO-SiO2 join is expected to yield insight into the origin of melt behavior including compression mechanisms and mixing properties; and c) Thermodynamics of mixing in silicate liquids through ab initio predictions of the volume and enthalpy of mixing as a function of composition along the MgO-SiO2 and albite-water joins. The proposed research is essentially an exploitation of ideas and techniques of computational science to challenging problems in the investigation of Earth materials. The cross-fertilization between studies of complex geochemical and earth materials issues on the one hand, and high-end computation on the other should be of benefit to both fields. To take full advantage of this aspect, the project will also initiate applications of the Access Grid - a facility that allows group-to-group multimedia network communication, to train students in this interdisciplinary effort.

该项目将应用基于密度泛函理论（DFT）的第一性原理方法来研究硅酸盐液体的物理化学性质，硅酸盐液体是地幔的主要组成部分。 该方法已被证明是对研究地球材料的各种晶体特性的实验方法的理想补充，在这里它将扩展到涉及相对大量原子的材料系统的模拟。这些大规模模拟将导致我们对大范围压力、温度和成分的硅酸盐液体的了解取得重大进展，这对于更好地了解行星演化至关重要，因为硅酸盐液体是行星内部热量和质量传输的主要手段。地球。 该项目将为理解以下内容做出重要贡献： a) 通过从头计算状态方程的硅酸盐液体的浮力，包括地幔压力-温度范围内的透辉石、顽火辉石和镁橄榄石成分的液体； b) 通过分析理论模拟中可用的完整结构信息（包括配位数、键长和键角）来确定硅酸盐液体的结构。对透辉石和水合钠长石成分的液体结构以及 MgO-SiO2 连接上的熔体进行分析，预计将深入了解熔体行为的起源，包括压缩机制和混合特性； c) 硅酸盐液体中混合的热力学，通过从头开始预测混合体积和混合焓作为沿着 MgO-SiO2 和钠长石-水连接处的组成的函数。拟议的研究本质上是利用计算科学的思想和技术来解决地球材料研究中的难题。 一方面复杂地球化学和地球材料问题的研究与另一方面高端计算之间的交叉融合应该对这两个领域都有利。 为了充分利用这方面的优势，该项目还将启动接入网格的应用——一种允许小组间多媒体网络通信的设施，以培训学生进行这一跨学科的努力。