Ultrahigh Pressure Studies of Hydrogen and Its Isotopes

这是在多兆巴压力范围内研究固体氢及其同位素氘和HD的新建议。压力将超过300 GPa，据信将发生解离过渡到原子金属氢。这将在新设计的精密金刚石砧细胞中使用高质量的小块金刚石来完成。通过研究强红外吸收，以及从振子模式的拉曼散射，在被认为是转变为原子固体之前的a相中寻找转变。然后将通过光学技术研究检测到的相变，以观察低温下的德鲁德自由电子行为或直流电导电性，以确定导电状态。核磁共振将用于确定邻对位转化率。将发展光学技术来确定折射率或折射率和状态方程。这是在多兆巴压力范围内研究固体氢及其同位素氘和HD的一个新建议。固体氢和它的同位素有迷人的高压相图。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。预测分子金属和原子金属可能成为室温超导体。在大约1.5兆巴的速度下向称为A相的相变仍然不为人所知。这些固体将在几兆巴压力下使用新设计的精密金刚石砧细胞进行研究。红外吸收和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。核磁共振将用于确定邻对位转化率。光学技术也将发展，以确定折射率和状态方程。＊＊＊

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. ***