Physics and Chemistry of Planetary Materials under Extreme Pressure and Temperature Conditions

我研究的目的是提高我们了解地球和其他行星内部深层动力学和进化的能力。地球和行星内部的动力学和进化将影响地球和其他行星的最外层特征。然而，它们的内部是无法进入的，不能直接调查。另一种方法是在类似于地球和行星内部的模拟环境中研究地球和行星材料。重要的是，材料在环境条件下（1atm和25c）的行为与它们在更深的深度下的表现不同。因此，只有在与一定深度相对应的压力(P)和温度(T)条件下收集的数据才能有效地模拟地球和行星内部的结构和动力学。因此，在P-T条件下对地球和行星材料的研究为了解地球和行星内部的动力学和进化提供了一种有希望的方法。我的研究计划使用钻石砧细胞（DAC，能够产生P到3,000,000 atm）以及电阻和激光加热方法（能够将样品加热到300-4000 K），在极端P- t条件下研究行星材料。广泛的P-T范围（1-3,000,000 atm和300- 4,000 K）使我们能够复制地球和行星内部的条件。此外，利用定制的微拉曼系统和同步加速器x射线光谱学，研究了相关材料的光谱特性。在本研究中，我们合成了深部地幔重要相（含氮硅酸盐和氮化铁、尖晶石、含锆硅酸盐和氧化物），并利用同步加速器x射线衍射、x射线光谱学、拉曼散射和布里渊散射对它们进行了表征，以了解它们的结构和物理性质（密度、体积、弹性、强度、声速）。将合成的样品淬火到环境条件下，通过电子探针微分析和扫描电镜检查，以了解元素的分配和元素在样品中的分布，铁氮化物的熔化标准，以及纳米级相的晶体结构。我们的目标是(1)评估地球内部和其他行星内部的N预算，这对未来的行星探索很重要；(2)了解地球深部地震异常（如超低速度）的原因和机制；(3)评估高P-T条件下的铬铁矿尖晶石多晶及其与冲击陨石的联系；(4)研究常见的行星冰（CO2, N2, CH4, CH4, co）的强度。NH3)，可用于模拟行星内部的动力学。HQP将接受高P-T矿物物理方面的广泛培训，提供可转移的技能，为他们在学术、政府和私营部门就业做好准备。

The objective of my research is to improve our abilities to understand the deep interior dynamics and evolution of Earth and other planets. The dynamics and evolution of Earth's and planetary interiors will influence the outermost features of the Earth and other planets. However, their interiors are inaccessible and cannot be directly investigated. Alternative approaches are to study Earth and planetary materials at simulated environments that are similar to Earth and planetary interiors. Importantly, behavior of materials at ambient conditions (1 atm and 25 C) is different from what they exhibit at greater depths. Therefore, only those data collected at pressure (P) and temperature (T) conditions corresponding to the certain depths are valid for modeling the structure and dynamics of the Earth's and planetary interiors. Therefore, study of Earth and planetary materials at P-T conditions corresponding to their deep interiors provide a promising approach to understand the dynamics and evolution of Earth's and planetary interiors. My research program uses a diamond-anvil cell (DAC, able to generate P to 3,000,000 atm) together with resistive and laser heating methods (able to heat the sample to 300-4000 K), to study planetary materials under extreme P-T conditions. The extensive P-T ranges (1-3,000,000 atm and 300-4000 K) allow us to replicate the conditions found within the Earth and planetary interiors. Moreover, using a custom-built micro-Raman system and synchrotron X-ray spectroscopy, the spectroscopic properties of relevant materials are also examined. In this proposal, we synthesize the important deep mantle phases (e.g. N-bearing silicates and iron nitrides, spinels, Zr-bearing silicates and oxide) and characterize them using synchrotron x-ray diffraction, x-ray spectroscopy, Raman and Brillouin scattering to understand their structures and physical properties (e.g. density, volume, elasticity, strength, sound velocity). The synthesized samples when quenched to ambient conditions will be examined by electron probe microanalysis and scanning electron microscopy for understanding the partitioning of the elements and element distributions within the samples, the melting criteria of the iron nitrides, and the crystal structures of the nano-scale phases. Our goals are (1) to evaluate the budgets of the N inside the Earth and other planetary interiors which is important for future planet explorations, (2) to understand the causes and mechanism of seismic anomalies (e.g. ultralow velocity) in deep Earth, (3) to evaluate the chromite spinel polymorphs at high P-T conditions and its connection to the shocked meteorites, and (4) to study strength of popular planetary ice (CO2, N2, CH4, NH3) that can be applied to modeling the dynamics of the planetary interiors. HQP will receive extensive training in high P-T mineral physics that will provide transferable skills to prepare them for employment in academic, government and private sectors.