Ultrahigh Pressure Studies of Hydrogen and Its Isotopes

氢及其同位素的超高压研究

• 批准号: 9701500
• 负责人: Isaac Silvera
• 金额: $ 36万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2001-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9701500&HistoricalAwards=false
• 关键词: Ultrahigh; Pressure; Studies; Hydrogen; Its

9701500 Silvera This is a new proposal to study solid hydrogen and its isotopes, deuterium and HD in the multimegabar pressure range. Pressures will be extended beyond 300 GPa, where it is believed that the dissociative transition to atomic metallic hydrogen will take place. This will be accomplished using high quality, small culet diamonds in newly designed precision diamond anvil cells. Transitions will be searched for by studying the strong IR absorption, as well as the Raman scattering from vibron modes, in the A-phase which is believed to precede the transformation to the atomic solid. A detected phase transition will then be studied by optical techniques to observe Drude free-electron behavior, or dc electrical conductivity at low temperature, in order to determine the conductive state. NMR will be used to determine ortho-para conversion rates. Optical techniques will be developed to determine the index or refraction and the equation of state. %%% This is a new proposal to study solid hydrogen and its isotopes, deuterium and HD in the multimegabar pressure range. Solid hydrogen and its isotopes have fascinating high pressure phase diagrams. These molecular solids are predicted to become molecular metals at pressures between 1.5 and 3 megabar and atomic metals at higher pressures. The molecular and atomic metals are predicted to be possible room temperature superconductors. A transition to a phase called the A-phase at about 1.5 megabars is still not understood. These solids will be studied at multimegabar pressures using newly designed precision diamond anvil cells. IR absorption, as well as Raman scattering will be used to search for new phases. These will then be studied by optical techniques or dc electrical conductivity at low temperature to observe possible metallic behavior. NMR will be used to determine ortho-para conversion rates. Optical techniqu es will also be developed to determine the index of refraction and the equation of state. ***

小行星9701500 这是研究固体氢及其同位素、氘和氘代氢的一个新的设想， 数兆巴压力范围。 压力将超过300 GPa，据信将发生向原子金属氢的解离过渡。 这将通过在新设计的精密金刚石砧单元中使用高质量的小底尖金刚石来实现。 转变将通过研究强IR吸收以及来自振子模式的拉曼散射来搜索，在A相中，A相被认为先于向原子固体的转变。 一个检测到的相变，然后将研究通过光学技术观察德鲁德自由电子 行为或直流电导率 在 低温，以确定导电状态。 NMR将用于确定邻-对位转化率。 将发展光学技术来确定折射率和状态方程。 这是一个研究固体氢及其同位素氘和氢同位素的新建议。 数兆巴压力范围。 固体氢及其同位素具有迷人的高压相图。 预计这些分子固体在1.5到3兆巴的压力下会变成分子金属，在更高的压力下会变成原子金属。 分子和原子金属被预测为可能的室温超导体。 在大约1.5兆巴的时候，过渡到一个被称为A相的阶段仍然不清楚。 这些固体将在几兆巴的压力下使用新设计的精密金刚石砧细胞进行研究。 红外吸收，以及拉曼散射将用于寻找新的相。 然后将通过光学技术或低温下的直流电导率来研究这些材料，以观察可能的金属行为。 NMR将用于确定邻-对位转化率。 还将发展光学技术来确定折射率和状态方程。 ***