Hydrogen at Ultra-High Pressure

超高压氢气

• 批准号: 0804378
• 负责人: Isaac Silvera
• 金额: $ 45.5万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0804378&HistoricalAwards=false
• 关键词: Hydrogen; Ultra; Pressure

TechnicalThis individual investigator award will support studies of hydrogen at ultra high pressures and temperatures. Earlier attempts to study hydrogen in the high-pressure high-temperature regime were thwarted by diffusion of hydrogen in the pressure cell materials and loss of sample or embrittlement and failure of cell materials. By utilizing pulsed laser heating this problem has been overcome since the time that the sample is hot and can diffuse is limited to the short time of the pulse. The emphasis will be on studies along and above the melting line of hydrogen. Hydrogen was predicted to have a peak in its melting line and this peak was recently experimentally demonstrated to occur below a megabar. The melting line studies will be extended to higher pressures. At lower pressures hydrogen melts from a molecular solid to a molecular liquid. With increasing temperature above the melting line hydrogen will dissociate and become monatomic with metallic conductivity. With increasing pressure beyond the peak the melting temperature may descend to zero Kelvin and one may observe melting directly from the molecular to the atomic phase. The atomic metallic liquid is expected to demonstrate two-component superconductivity (electrons and protons) as well as superfluidity Metallic hydrogen is predicted to be metastable due to a potential barrier. This barrier between the two phases may be responsible for inhibiting the transition from solid molecular to atomic metallic at low temperature. At high temperature thermal energy may allow the molecular phase to overcome the barrier and make the transition to metallic hydrogen. The broader impact of this research is the development of new methods to study materials under extreme conditions enriching the scientific community. This program involves young researchers at all levels-high school, undergraduate, graduate, and postdoctoral, as they develop to become the scientists of the future.Non-technicalOver 70 years ago Wigner and Huntington predicted that at high pressure hydrogen will transform from a molecular solid to an atomic metallic solid, later predicted to be a possible room temperature superconductor (no resistance to the flow of electricity) that is metastable, i.e., will remain in the metallic phase when pressure is released. Because of its extreme quantum nature, theory is challenged to make accurate predictions of hydrogen's properties and needs experimental guidance. Hydrogen has been pressurized to more than 10 times the predicted transition pressure and remains molecular insulating. Recent theory predicted a peak in the melting line and with pressure increasing beyond the peak the melting temperature could descend to zero Kelvin. Hydrogen would be an atomic metallic liquid with superconductivity of both the electrons and protons. Earlier attempts to study hydrogen in the extreme pressure-temperature regime were frustrated due to the proclivity for hydrogen to diffuse out of the high pressure apparatus or into the materials comprising the apparatus at high temperature. Using a newly developed method of pulsed laser heating, hydrogen can now be studied in this regime. The predicted peak in the melting line has been observed and this research program will extend studies to higher pressures in search of the metallic state. On a broader level, new techniques for high pressure and high-temperature/low-temperature are developed for the scientific community; if metallic hydrogen can be produced and is metastable it will be a high energy density material as well as the most powerful rocket propellant available to man. Students and postdoctoral fellows on all levels, the next generation of scientists, are involved in the developments and research.

技术这项个人研究者奖将在超高压力和温度下支持对氢的研究。 通过在压力池材料中扩散氢以及样品或封闭材料的损失以及细胞材料的失败，挫败了早期研究在高压高温方向上进行氢气的尝试。 通过利用脉冲激光加热，自样品很热并且可以扩散的时间限于脉冲短时间以来，就已经克服了此问题。重点是沿氢熔融线的研究。 预计氢在其熔线上具有峰值，并且最近在实验中证明了该峰发生在兆巴以下。熔线研究将扩展到更高的压力。在下部压力下，氢从分子固体融化为分子液体。随着温度升高，熔融线氢将分离并随着金属电导率而变为单原子。随着压力的增加，熔化温度可能会下降到零开尔文，并且可能会直接从分子到原子相熔化。 预计原子金属液体将证明两种成分的超导性（电子和质子）以及由于潜在的屏障，预计将预计金属氢的超导性金属氢。 这两个阶段之间的障碍可能负责抑制在低温下从固体分子到原子金属的过渡。在高温下，热能可能使分子相可以克服屏障并将过渡到金属氢。这项研究的更广泛的影响是开发新方法，以在极端条件下富含科学界的材料研究。 该计划涉及各级学校，本科，毕业生和博士后的年轻研究人员，随着他们的发展成为未来的科学家。70年前的Non-technicalover wigner and Huntington预测，高压氢将从分子固体转变为分子固体变为原子固体，后来预测的是一种电力，这可能是一种能力的电阻（可能是室温超高剂量的，都可以通过超高的能力来启动，并且可以通过高度超高的态度来实现，从而可以通过含量超高剂，可以通过含量超高剂，可以通过耐心效果来实现，并且可以通过室温超级固定，而不是室温，而不是室内固体，而不是室温。即，当释放压力时，将保持金属相。 由于其极端的量子性质，理论是挑战的，以对氢的性质进行准确的预测，并需要实验指导。 氢已加压到预测过渡压力的10倍以上，并保持分子绝缘。 最近的理论预测，熔融线的峰值峰值，并且随着压力的增加，熔化温度可能下降到零开尔文。 氢将是一种原子金属液体，具有电子和质子的超导性。 由于氢气从高压设备中散射出氢或在高温下包含设备的材料中，因此挫败了在极高压力温度方面进行氢气的早期尝试。使用新开发的脉冲激光加热方法，现在可以在该方案中研究氢。 已经观察到熔融线中的预测峰值，该研究计划将将研究扩展到更高的压力，以寻找金属状态。 在更广泛的水平上，科学界开发了高压和高温/低温的新技术。如果可以产生金属氢并具有亚稳态，则将是高能量密度材料，也是人类可用的最强大的火箭推进剂。下一代科学家在各个层面上的学生和博士后研究员都参与了发展和研究。