Solid State Geochemistry: High-Resolution Transmission Electron Microscopy of Minerals

对于具有地球物理意义的岩石矿物，将以前所未有的细节确定近原子尺度上的材料特性和结构扰动。定量测量将包括：作为位错密度的函数的小角度晶界的波浪度；位错和晶界产生的细小尺度的位移和应变；位错核心附近的空间分辨应变-能量密度--这是以前无法到达的区域；以及位错的应变场和能量。将使用几何相分析，它结合了高分辨率电子显微镜和密集的图像分析。这些测量结果将与使用弹性理论的计算结果进行比较。在这一过程中，将确定从晶体结构破裂到接近一个或两个原子间距的区域的弹性常数的估计。这些结果将对材料性质产生影响，包括变形、再结晶、扩散、电学性质和其他地球物理参数。从应用的角度来看，某些宏观边界几何图形将提供可用于设计所需特性的曲率。具有不同背景和种族的学生和博士后研究人员将被提供一个跨学科的研究环境，并将接受在纳米尺度上学习材料的先进方法的培训。将开发研究地质材料的新方法；这些程序和数据也将对从事固态物理、化学和材料科学工作的科学家有用。研究成果将通过在具有广泛读者群的主要期刊上迅速发表来传播。国际组成部分是通过经常使用我们的设施和技术并将其出口到本国机构和国家的游客提供的。

Material properties and structural perturbations at the near-atomic scale will be determined with unprecedented detail for rock-forming minerals having geophysical significance. Quantitative measurements will be made of: the waviness of low-angle grain boundaries as a function of dislocation densities; fine-scale displacements and strain produced by dislocations and grain boundaries; the spatially resolved strain-energy density near dislocation cores - regions that were previously inaccessible; and the strain fields and energies of dissociated dislocations. Geometric phase analysis, which combines high-resolution transmission electron microscopy and intensive image analysis, will be used. The measurements will be compared to calculations utilizing elastic theory. In the process, estimates of elastic constants for regions as close as one or two atomic spacings from crystallographic disruptions will be determined. The results will have implications for material properties that include deformation, recrystallization, diffusion, electrical properties and other parameters of geophysical interest. From an applied perspective, certain macroscopic boundary geometries will give curvatures that could be exploited to engineer desired properties. Students and postdoctoral researchers with diverse backgrounds and ethnicities will be provided an interdisciplinary research environment and will be trained in advanced methods of studying materials at the nanoscale. New methodologies for studying geologic materials will be developed; the procedures and data will also be useful for scientists working in solid-state physics, chemistry, and materials science. The products of the research will be disseminated via prompt publication in leading journals with broad readership. An international component is provided through visitors who routinely utilize our facilities and techniques and export them to their home institutions and countries.