| Project/Area Number |
25400381
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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, 教授 (90202522)
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| Research Collaborator |
NAKANO Satoshi
SUGIMOTO Toshiyuki
MIZUKI Yu-to
MIYAMOTO Ryosuke
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| Project Period (FY) |
2013-04-01 – 2016-03-31
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| Project Status |
Completed (Fiscal Year 2015)
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| Budget Amount *help |
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2015: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2014: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2013: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
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| Keywords | 金属水素 / 超高圧 / X線回折 / 固体水素III相 / 高圧ラマン散乱 / ダイヤモンドアンビルセル / 放射光 / 高圧科学 / 固体水素 / 高圧相 / X線構造解析 / 金属化 / ラマン散乱 / ダイヤモンドアンビル |
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| Outline of Final Research Achievements |
The high-pressure phase (phase III) of molecular solid hydrogen is predicted to become metallic at high pressure. However, the structure of phase III still remains unidentified experimentally. We succeeded to obtain x-ray structure data of phase III of solid hydrogen at pressure up to 200 GPa under low temperature of 100 K using synchrotron X-ray diffraction technique at SPring-8. From the results, it was found that the molecular center of H2 is located in the vicinity of lattice points of hcp at least to 200 GPa and the c/a ratio of lattice constants decreased at the transition and reached 1.54 at 190 GPa. Considering the hydrogen molecule has an ellipsoidal shape and each molecular axis is ordered to tilt against the c axis of the hcp structure, the lattice parameter, c should contract. From Raman scattering experiments up to 300 GPa, clear splitting of low frequency Raman bands around 230 GPa was observed and asymmetrization of the hcp structure was revealed at the pressure.
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