液体水中の超高速水素結合の直接観測
Jie Yang1,2,3, Riccardo Dettori4, J Pedro F Nunes5
1SLAC National Accelerator Laboratory, Menlo Park, CA, USA. jieyang1@tsinghua.edu.cn.
Nature
|August 26, 2021
まとめ
研究者は超高速の電子散乱を用いて水中の一時的な水素結合の収縮を観察した. この発見は 水の振動の分子間性質を明らかにし 水素結合と化学反応を理解する鍵となるものです
科学分野:
- 物理化学
- 化学物理学
- 材料科学
背景:
- 液体の水は水素結合のネットワークにより 異常な性質を示します
- 超高速の振動運動を理解することは 水素結合のダイナミクスと化学反応に不可欠です
- 原子の運動と水素結合のダイナミクスを直接解明するには,既存のスペクトロスコピーの方法が困難です.
研究 の 目的:
- 振動刺激に対する液体の超高速構造反応を直接測定する.
- フェムト秒の時間スケールで水素結合のダイナミクスを解明する.
- 水の振動の分子間の性質を調査する.
主な方法:
- 液体超高速電子散射 (UFES) を利用し,フェムト秒の時間および原子の空間解像度を実現した.
- 液体の水でOHの振動を刺激した.
- 量子力学的プロトン分布を組み込んだ分子動力学シミュレーションを行った.
主要な成果:
- 80フェムト秒以内に約0.04 Åの一時的な水素結合の収縮を観測した.
- ピコ秒のスケールで発生する 熱化の過程を特定した.
- シミュレーションにより,フェムト秒ダイナミクスを正確にモデル化するために,陽子分布の量子力学的処理の必要性が強調されました.
結論:
- この研究は,液体の水の水素結合ネットワークの超高速構造変化の直接的な実験的証拠を提供します.
- 原子の運動と水素結合のダイナミクスを 見ることができます
- この発見は,OHのストレッチリラクゼーションに先立つ水の分子間性質を強調し,正確なモデリングのために量子力学的な考慮が必要である.
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