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

我的研究目的是提高我们了解地球和其他行星的深部内部动力学和演化的能力。地球和行星内部的动态和演化将影响地球和其他行星的最外层特征。然而，他们的内部无法接触到，也无法直接调查。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(1大气压和25摄氏度)下的行为与它们在更深处的表现不同。因此，只有在与一定深度对应的压力(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，研究地球和行星物质在与其深部相对应的P-T条件下的变化，为理解地球和行星内部的动力学和演化提供了一种很有前途的途径。*我的研究项目使用钻石顶压室(DAC，能够产生P到3,000,000大气压)以及电阻和激光加热方法(能够将样品加热到300-4000 K)，在极端的P-T条件下研究行星材料。广泛的P-T范围(1-300万大气压和300-4000K)使我们能够复制在地球和行星内部发现的条件。此外，利用定制的显微拉曼系统和同步辐射X射线光谱，还研究了相关材料的光谱性质。*在这个方案中，我们合成了重要的深部地幔相(例如，含N的硅酸盐和氮化铁，尖晶石，含Zr的硅酸盐和氧化物)，并用同步加速器x射线衍射，x射线光谱，拉曼和布里渊散射来表征它们，以了解它们的结构和物理性质(如密度，体积，弹性，强度，声速)。合成的样品在室温下淬火后，将用电子探针和扫描电子显微镜进行分析，以了解样品中元素的分配和元素分布，氮化铁的熔化准则，以及纳米相的晶体结构。我们的目标是(1)评估地球内部和其他行星内部的N的预算，这对未来的行星探索是重要的；(2)了解地球深部地震异常(例如超低速)的原因和机制；(3)评估高P-T条件下的铬铁矿尖晶石多晶型及其与受冲击的陨石的联系；(4)研究流行的行星冰(CO_2，N_2，CH_4，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，这些培训将提供可转移的技能，为他们在学术、政府和私营部门就业做准备。

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.**