Phase Transitions and Volume and Energy Band Gap Variation in the Multimegabar Regime

将开发用于x射线衍射研究（使用康奈尔高能同步加速器服务）和光学研究的技术，这些技术将把静压范围扩大到560 GPa以上。要做到这一点，需要进一步缩小金刚石尖端、样品尺寸、x射线孔径和光束直径。氧和硫的晶体结构会被发现吗？先前已经金属化的材料（在高压下，它们在金刚石样品界面上具有60%的反射率）！因为这将促使理论家研究这些材料。将在其中寻找超导行为。氢气，氮气（包括高温）和LiH将被加压到超过4毫巴或更高的压力，目的是达到肉化。将研究碱氢化物作为类似系列的金属化，氢化物是该系列的最高成员。超高压引起固体的巨大变化。固体氙在1.5毫巴时体积减少72%，而硅在2.5毫巴时体积减少34%（地核的压力为3.6毫巴，海洋最深处的压力仅为1kbar）。这些巨大的变化引起晶体结构的变化，电子结构的变化导致物理性质的重要变化。理论家们使用近似的量子力学（使问题易于解决所必需的）试图计算这些结构变化。结果为他们的理论提供了一个严格的测试，并为基于计算机的固体物理学奠定了基础。人们还对开发可能具有特殊性能的新材料感兴趣。据预测，氢在高压下会变成金属，是高温超导体。金属氙和金属氧已经被制造出来，人们正在努力制造金属氢，看看它是否确实是高温超导体。高压被视为制造和加工具有特殊性能的新材料的工具。

Techniques for x-ray diffraction studies (using Cornell High Energy Synchroton Service) and optical studies which will extend the static pressure range higher than the 560 GPa attained will be developed. To do this requires further miniaturization of diamond tips, of sample size and of x-ray apertures and optical beam diameters. The crystal structure of oxygen and sulfur will be found ?materials which have previously been metallized (they have 60% reflectivity at the diamond sample interface at high pressure)! since this should induce theorists to work on these materials. Superconductive bahavior will be looked for in them. Hydrogen, nitrogen (including high temperature) and LiH will be pressurized to pressures in excess of 4 Mbars and higher with the intent of reaching meatllization. The metallization of alkali hydrides as an analogous series with hydrogen hydride as the highest member of the series will be studied. %%% Ultrapressures cause enormous changes in solids. Solid xenon has its volume decreased by 72% at 1.5 Mbars while silicon has its volume decreased by 34% at 2.5 Mbars (the pressure at the earth's core is 3.6 Mbars and at the deepest spot in the ocean only 1kbar). These enormous changes cause changes in crystal structure, and changes in electronic structure resulting in important changes in physical properties. Theorists, using quantum mechanics with approximatims (necessary to make the problem soluble) attempt to calculate these structural changes. Results provide an exacting test of their theories and set the stage for doing computer based solid state physics. Interest is also in developing new materials with possible exotic properties. It has been predicted that hydrogen will become metallic at high pressure and that it will be a high temperature superconductor. Metallic xenon and metallic oxygen have been made and work is being done to make metallic hydrogen to see if it indeed is a high temperature superconductor. High pressure is viewed as a tool for making and processing new materials with unusual properties.