Mbar Chemistry: Novel States of Matter at Extreme Conditions

技术摘要：高压的应用显著改变了原子间的距离，从而改变了分子间相互作用的性质、化学键、分子构型、晶体结构和固体的稳定性。随着现代高压技术的进步，实现晶格的大压缩(通常高达几倍)是可行的，在这种条件下，材料可以很容易地被强迫进入新的物理和化学构型。因此，高压提供了更多的机会来发现新的相，包括稳定和亚稳定的相，并在很大的原子长度范围内调整新的性质，大大大于(通常是几个数量级)通过其他热(变化的温度)和化学(变化的成分或制造合金)方法获得的。这项拟议的工作的目标是研究物质的新状态和在Mbar压力下发生在简单的低Z分子中的新现象，如二氧化碳和氮。通常在这些条件下观察到的是金属和非金属扩展固体，它们可以在其三维网络结构中存储大量的能量。然而，低Z固体的大结合能导致了极硬的晶格和新颖的电子和光学性质。广泛地说，这些分子到非分子的转变是由于电子离域而发生的，表现为高密度下电子动能的快速增加，但关于化学键的确切性质、相稳定性和化学机制仍有许多突出的问题。许多问题是固态化学和凝聚态物理中的基本问题，这些问题将在本项目中解决。非技术概述：本提案中概述的研究将影响基础固态化学和凝聚态材料科学，这最终将在MBARS建立新的元素和固体的周期秩序。该项目还将通过在华盛顿州立大学(WSU)以及同步加速器设施和国家实验室提供尖端实验技术的实践研究经验，对研究生和本科生的培训产生重大影响。这项研究将为斯波坎和附近地区的科学家和学生带来高压材料研究的兴奋，远远超出WSU的范围，从而提高公众对基础材料研究与未来和社会相关性的认识。因此，该项目的好处远远超出了这项建议的直接科学范围。

TECHNICAL SUMMARY: Application of high pressure significantly alters the interatomic distance and, thus, the nature of intermolecular interaction, chemical bonding, molecular configuration, crystal structure, and stability of solid. With modern advances in high-pressure technologies, it is feasible to achieve a large (often up to a several-fold) compression of lattice, at which condition material can be easily forced into a new physical and chemical configuration. The high-pressure thus offers enhanced opportunities to discover new phases, both stable and metastable ones, and to tune novel properties in a wide-range of atomistic length scale, substantially greater than (often being several orders of) those achieved by other thermal (varying temperatures) and chemical (varying composition or making alloys) means.The goal of this proposed work is to investigate new states of matter and novel phenomena occurring in simple low-Z molecules like carbon dioxide and nitrogen at Mbar pressures. Commonly observed at these conditions are metallic and nonmetallic extended solids that can store a large sum of energy in their three-dimensional network structures. Yet, a large cohesive energy of low Z solids gives rise to an extremely stiff lattice and novel electronic and optical properties. Broadly speaking, these molecular-to-nonmolecular transitions occur due to electron delocalization manifested as a rapid increase in electron kinetic energy at high density, but there are many outstanding questions regarding the exact nature of chemical bonding, phase stability, and chemical mechanisms. Many of the questions are fundamental problems in solid state chemistries and condensed matter physics, which will be addressed in this project.NON-TECHNICAL SUMMARY: The research outlined in this proposal will impact fundamental solid-state chemistries and condensed materials sciences, which will eventually establish new Periodic orders of elements and solids at Mbars. The project will also have significant impacts on training graduate and undergraduate students by providing hands-on research experiences in cutting-edge experimental technologies at Washington State Univerisity (WSU) and at synchrotron facilities and national laboratories. The present study will bring the excitement of high-pressure materials research to the scientists and students in Spokane and nearby areas well beyond the WSU and, thus, enhance public appreciation of the relevance of fundamental materials research to the future and society. Hence, the benefits of the project reach well beyond the immediate scientific scope of this proposal.