Structure analysis of solid hydrogen III phase using high-pressure X-ray diffraction technique
| Project/Area Number |
17K05550
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | University of Hyogo |
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Principal Investigator |
Akahama Yuichi 兵庫県立大学, 物質理学研究科, 特任教授・名誉教授 (90202522)
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| Project Period (FY) |
2017-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2017: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
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| Keywords | 水素 / 高圧固体相 / X線回折 / 金属化 / 超臨界流体相 / ラマン分光 / 放射光 / ダイヤモンドアンビル / 固体水素 / 高圧相 / X線回折実験 / 超臨界相 / 高圧構造 / X線構造解析 / ラマン散乱 / 超高圧 / 分子性固体 / 超高圧力 / 金属水素 / 高温超伝導 |
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| Outline of Final Research Achievements |
For the first time in the world, we succeeded in observing a high-quality powder X-ray diffraction pattern from the solid hydrogen phase III up to 200 GPa. Based on the observed data, it was clarified that the phase III structure has hexagonal symmetry, and that the hydrogen molecule is still near the lattice point of the hcp structure even at 200 GPa. So far, a monoclinic lattice (C2/c) has been regarded as promising for the structure of phase III from theoretical studies, but this result overturned this prediction and prompted a reexamination of theoretical calculations. Our Raman spectroscopy also clarified that the phase III caused a low symmetry of the crystal structure at about 230 GPa. Furthermore, the correlation between density and molecular vibration for the hydrogen supercritical fluid phase was found from X-ray diffraction and Raman spectroscopy experiments, and the pressure-induced structural phase transitions of many elemental materials were clarified.
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| Academic Significance and Societal Importance of the Research Achievements |
水素は、最も単純な元素で、科学研究における重要な対象物質である。400 GPa以上の超高圧力下で実現すると予言されている金属水素は、室温で超伝導を示すことが提案され固体物理学の分野の重要課題となっている。本研究で解明された固体水素Ⅲ相の結晶構造、密度そして分子振動に関する情報は、金属水素を実現し、金属相の物性を理解する上で貴重な基礎データであり、学術的に大きな意義がある。また、本研究により解明された水素超臨界流体相の光学的性質や凝集状態そして密度等の基礎物性は、水素社会実現のための高圧水素ガス応用の上で貴重なデータに成ることから社会的に意義があると確信している。
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Report
(5 results)
Research Products
(35 results)
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[Journal Article] Piezofluorochromism in Charge‐Transfer Inclusion Crystals: The Influence of High Pressure versus Mechanical Grinding2018
Author(s)
Toshikazu Ono, Yoshifumi Tsukiyama, Ai Taema, Hiroyasu Sato, Hidetoshi Kiyooka, Yuma Yamaguchi, Ayumi Nagahashi, Manami Nishiyama, Yuichi Akahama, Yoshiki Ozawa, Masaaki Abe, Yoshio Hisaeda
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Journal Title
ChemPhotoChem
Volume: 印刷中
Issue: 5
Pages: 416-420
DOI
Related Report
Peer Reviewed / Open Access
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[Presentation] Volume compression of period 4 elements: Zn, Ge, As, and Se up to multimegabar pressures2019
Author(s)
Y. Akahama, K. Kamiue, N. Okawa, S. Kawaguchi, N. Hirao, and Y. Ohishi
Organizer
The 57th European High Pressure Research Group Meeting on High Pressure Science and Technology: (EHPRG2019) September 1-6, 2019, Hotel Duo, Prague, Czech Republic
Related Report
Int'l Joint Research
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[Presentation] Reentrant structure transition of indium at 130 GPa2018
Author(s)
Y. Akahama, K. Kamiue, K. Takahashi, N. Hirao, and Y. Ohishi
Organizer
The 18th International Conference on High Pressure in Semiconductor Physics (HPSP-18) & The Workshop on High pressure Study on Superconducting (WHS), (Barcelona, Spain July 23-27, 2018)
Related Report
Int'l Joint Research
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