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.

该项目将基于密度功能理论（DFT）采用第一原理方法来研究硅酸盐液体的物理化学特性，硅酸盐液体是地球地幔的主要成分。 该方法已经被证明是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。这些大规模的模拟将导致我们对硅酸盐液体在大的压力，温度和成分中的了解，这对于更好地理解行星进化至关重要，因为硅酸盐液体是地球内部热和质量运输的主要手段。 该项目将通过从头开始预测国家方程，包括硅酸盐方程，包括二北方，enstatite液体和玻璃石的液体在地幔的压力温度方面，从而为理解：a）硅酸盐液体的浮力做出关键贡献； b）通过分析完整的结构信息的结构，这些信息在理论模拟中可用，包括协调数，键长和键角。分析Diopside液体和含水albite组成的液体的结构，并有望在MGO-SIO2连接上进行融化，可预见融合熔体行为的起源，包括压缩机制和混合特性； c）通过从头开始预测混合的体积和焓作为沿MGO-SIO2和Albite - 水连接的组成的函数，通过硅酸盐液体中混合的热力学。拟议的研究实质上是对计算科学的思想和技术对地球材料调查中挑战性问题的剥削。 一方面，对复杂地球化学和地球物质问题的研究与另一方面的高端计算之间的交叉剥夺应对这两个领域都有好处。 为了充分利用这一方面，该项目还将启动访问网格的应用程序，该设施允许小组到小组多媒体网络通信，以培训学生进行这项跨学科工作。