CaSiO3液体高压输运性质的理论研究

Silicate liquids with high physically mobile and chemically active are the main constituents of the Earth's lower mantle. They are crucial carriers for the transfer of matter and heat in the Earth and plausibly other terrestrial planets, thus play a key role in petrologic and geodynamic processes throughout the formation and evolution of Earth's internal spheres. The high-pressure transport properties of silicate liquids are of extreme importance to understanding cooling and crystallization of Earth's early magma ocean, as well as mantle dynamics nowadays. CaSiO3 liquid is one of the main components of the Earth's lower mantle. In this project, we propose to study systemically the structure, equations of state, thermodynamic and transport properties of CaSiO3 liquid over the entire mantle pressure-temperature regime using empirical pair-potential and ab initio molecular dynamics methods. In combination with the previous results of other silicate liquids, this study might improve our understanding of not only magma generation and transport, but also the chemical and thermal evolution of the Earth. In addition, the expected results could provide important parameters for establishing the geophysical and geochemical models of the mantle matters. This proposal works on the cross point of the earth's deep physics and the condensed matter physics, therefore, it could also deepen the understanding of the basic physical issues of the liquid substance.

硅酸盐液体是地球下地幔的重要组分，它具有高度的物理和化学活性，是地球乃至其他类地行星内部物质和能量迁移的重要载体，它们在地球内部层圈形成和演化的岩石学和动力学过程中发挥了关键作用。其高压输运性质对充分了解地球早期岩浆洋的冷却和结晶以及现今地幔动力学至关重要。CaSiO3液体是地球下地幔的主要组分之一，本项目拟分别利用经验对势和从头算分子动力学方法，比较系统地研究下地幔温度和压力范围内CaSiO3液体的结构、物态方程、热力学性质和输运性质，并结合前人对其他下地幔硅酸盐液体的研究结果，深化对下地幔岩浆的生成和输运以及地球的化学和热演化的理解，为建立下地幔物质的地球物理和地球化学模型提供重要的物理参数。本课题具有地球深部物理与凝聚态物理交叉学科研究性质，对深化有关液态物质基础物理问题的认识亦有重要意义。

固体材料的辐照效应直接关系到在核反应堆、航天器和其他辐射场中工作的各种部件的功能指标和运转寿命，因此，研究解决材料的耐辐射问题和寻求辐照效应小的材料至关重要。本项目通过考虑电荷转移在辐照过程中的作用，采用从头算分子动力学模拟的方法，研究了部分固体材料及不同元素掺杂、缺陷、位错的结构、热力学性质、电子结构和含能性质及辐照效应。揭示了固体材料辐照损伤机制，获得了耐辐照性能的规律，创建了一套表征材料抗辐照性能的方法，获得了极端条件下固体材料的力学以及电学特性。为新型结构、功能材料的研发提供了重要的理论支持，这对人们认识固体材料在极端环境下结构与性能的演化发挥了关键作用，可加深人们对材料抗辐照性能和核能安全利用之间关系的认知。