Structure and Dynamics of Single-Crystalline Ice Ih Interfaces
Project/Area Number |
18H01934
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Research Category |
Grant-in-Aid for Scientific Research (B)
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Allocation Type | Single-year Grants |
Section | 一般 |
Review Section |
Basic Section 32010:Fundamental physical chemistry-related
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Research Institution | Saitama University |
Principal Investigator |
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Co-Investigator(Kenkyū-buntansha) |
野嶋 優妃 埼玉大学, 理工学研究科, 助教 (90756404)
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Project Period (FY) |
2018-04-01 – 2022-03-31
|
Project Status |
Completed (Fiscal Year 2021)
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Budget Amount *help |
¥17,160,000 (Direct Cost: ¥13,200,000、Indirect Cost: ¥3,960,000)
Fiscal Year 2021: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2020: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2019: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2018: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
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Keywords | 氷 / 分光 / 表面 / 界面 / 非線形 / 和周波 / 振動分光 / 和周波発生分光 / ヘテロダイン検出 / プロトン秩序 / 水 / 和周波発生 / 水素結合 / 氷Ih / 水素の位置の無秩序性 / 残余エントロピー / OH伸縮振動 / 振動スペクトル / 表面緩和 / 水分子の上下の配向 / ice rule / proton disorder / ヘテロダイン検出和周波発生 / 同位体希釈 / 単結晶氷Ih |
Outline of Final Research Achievements |
Among numerous crystalline phases of ice, the Ih phase is the most stable above 72 K at atmospheric pressure. It is well established that the orientations of water molecules in the bulk of ice Ih are statistical without long-range order. However, the orientational order of water at the surface of ice Ih has been enigmatic. Here we show that the surface of ice Ih at 100 K has hydrogen order with the OH group pointing upward to the air ("H-up" orientation). We applied nonlinear optical spectroscopy and theoretical modeling to the surface of isotopically pure and diluted ice Ih and observed OH stretch vibrational signatures attributed to H-up ordering. Furthermore, we found that this hydrogen order takes place despite more inhomogeneous microenvironment at the surface than in the bulk. Our results suggest the prominent role of the surface to allow the reorientation of water molecules for hydrogen ordering that is virtually prohibited in the bulk.
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Academic Significance and Societal Importance of the Research Achievements |
今回の研究で,氷Ihの表面はH-upの水素秩序構造を有することが分かったが,なぜそのような秩序が発生するのかは明らかでない.72 K以下のバルクでは,水素無秩序構造の氷Ihよりも水素秩序構造の氷XIの方が安定であることが知られているが,IhからXIへの相転移は欠陥の導入なしでは速度論的に不可能である.表面では水素結合ネットワークが切断され,水分子の並進と回転運動の自由度がバルクよりも大きく,フラストレーションがより小さい.それによって表面では水素秩序構造への“相転移”が速度論的に可能となっているのかもしれない.表面での秩序-無秩序転移の機構解明には,温度依存性の研究が将来的に重要になる.
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Report
(5 results)
Research Products
(7 results)