Simple Molecular Systems at Ultrahigh Pressure

超高压下的简单分子系统

• 批准号: 0508988
• 负责人: Russell Hemley
• 金额: $ 37.5万
• 依托单位: Carnegie Institution of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0508988&HistoricalAwards=false
• 关键词: Simple; Molecular; Systems; Ultrahigh; Pressure

*** NON-TECHNICAL ABSTRACT ***This project explores the nature of materials at extreme conditions -- pressures up to and beyond 3 million atmospheres (3 megabars), and temperatures from cryogenic conditions to thousands of degrees. Under these extreme conditions, simple liquids and gases can be converted to novel materials, including unusual metals and even superconductors. This research will examine the nature of these and related high-pressure transformations and will search for altogether new phenomena when simple materials are compressed to very high densities. As such, the work will expand our knowledge of fundamental interactions in condensed matter as well as lead to the creation of new materials. The experiments will make use of major national facilities such as new synchrotron radiation and neutron scattering sources. A wide cross-section of participants will benefit from the work, including high school students, undergraduates, graduate students, postdoctoral associates, and visiting investigators. In terms of its importance to fundamental science, potential applications to technology, and the training of scientists, the work is at the forefront of a rapidly growing area of the physical sciences.*** TECHNICAL ABSTRACT *** This individual investigator award will support continued studies of the behavior of simple molecular materials at pressures up to above 300 GPa (3 megabars) over a broad range of temperatures using recently developed diamond-anvil cell, synchrotron x-ray, neutron scattering, optical spectroscopy, and transport probes. The experiments will focus on transformations in representative solids formed from low-Z diatomic systems, rare gases, and dense compounds and alloys containing these species. Synchrotron x-ray and neutron diffraction techniques will be used to identify crystal structures of novel high-pressure phases of oxygen, nitrogen, and hydrogen, as well as of selected polyatomics and newly discovered high-pressure compounds. Raman, infrared, and optical spectroscopy will probe bonding, phase transformations, and electronic properties in these systems over a broader range of conditions, including measurements in the dense conducting fluid phase of hydrogen. The high-pressure behavior of stoichiometic hydrogen compounds, doped hydrogen systems, selected clathrates, and other molecular materials will also be investigated. High-pressure x-ray inelastic scattering will be used to measure pressure effects on dynamic structure factors and electronic structure, extending direct measurements of excitons and band gaps on compression. Highly sensitive magnetic susceptibility and new resistivity methods will be used to study superconductivity in these materials to the 300-GPa range. Each of these studies will involve the training of students, post-doctoral fellows, and other researchers in state-of-the-art condensed matter techniques.

该项目探索极端条件下材料的性质——压力高达或超过300万大气压（3兆巴），温度从低温条件到数千度。在这些极端条件下，简单的液体和气体可以转化为新的材料，包括不寻常的金属甚至超导体。这项研究将研究这些和相关高压转变的本质，并将在简单材料被压缩到非常高密度时寻找全新的现象。因此，这项工作将扩大我们对凝聚态物质基本相互作用的认识，并导致新材料的创造。实验将利用国家主要设施，如新型同步辐射和中子散射源。广泛的参与者将从这项工作中受益，包括高中生、本科生、研究生、博士后助理和访问研究者。就其对基础科学的重要性、对技术的潜在应用以及对科学家的培训而言，这项工作处于物理科学快速发展领域的前沿。***技术摘要***该个人研究者奖将支持在压力高达300 GPa（3兆巴）以上的广泛温度范围内使用最近开发的金刚石砧细胞，同步加速器x射线，中子散射，光谱学和传输探针对简单分子材料行为的持续研究。实验将集中于由低z双原子系统、稀有气体和含有这些物种的致密化合物和合金形成的代表性固体的转变。同步加速器x射线和中子衍射技术将用于识别氧、氮和氢的新型高压相的晶体结构，以及选定的多原子和新发现的高压化合物。拉曼、红外和光学光谱将在更广泛的条件下探测这些系统的键合、相变和电子特性，包括测量氢的致密导电流体相。化学计量氢化合物、掺杂氢系统、选定笼形物和其他分子材料的高压行为也将被研究。高压x射线非弹性散射将用于测量压力对动态结构因子和电子结构的影响，扩展了激子和带隙对压缩的直接测量。高灵敏度磁化率和新的电阻率方法将用于研究这些材料在300-GPa范围内的超导性。每一项研究都将涉及对学生、博士后研究员和其他研究人员进行最先进的凝聚态技术培训。