Characterization of hydrogen bonded transients in liquid water and ice by ultrafast infrared pump and x-ray absorption probe spectroscopy

通过超快红外泵和 X 射线吸收探针光谱表征液态水和冰中的氢键瞬态

• 批准号: 26519276
• 负责人: Professor Dr. Philippe Wernet
• 金额: --
• 依托单位: Institut für Optik und Atomare Physik (IOAP)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/26519276?language=en
• 关键词: Characterization; hydrogen; bonded; transients; liquid

Ordinary yet unique, liquid water is probably the most important and least understood substance on earth. A fluctuating network of hydrogen bonds connecting the constantly mobile molecules determines both structure and anomalous properties of water. The hydrogen bonds are strong enough to link the water molecules but they are also weak enough to constantly break and reform on an ultrafast time scale of 1 picosecond (10-12 seconds). Understanding the fast making and breaking of these bonds and the involved molecular rearrangements is a prerequisite for understanding structure and properties of water. We propose to elucidate the making and breaking of hydrogen bonds in water with an unprecedented combination of experimental techniques. The breaking of hydrogen bonds will be initiated by a controlled laser excitation. The subsequent evolution of the hydrogen bond network will be monitored on a molecular level and as a function of time by x-ray spectroscopy in a stroboscopic fashion (pump-probe scheme). This will give unique access to the short-lived early stages in the processes of hydrogen bond breaking and making and it promises to significantly advance our understanding of water.

普通但独特的液态水可能是地球上最重要、最不为人所知的物质。连接不断移动的分子的氢键波动网络决定了水的结构和反常性质。氢键足够强，可以连接水分子，但它们也足够弱，可以在1皮秒(10-12秒)的超快时间尺度上不断断裂和重塑。了解这些键的快速建立和断裂以及涉及的分子重排是了解水的结构和性质的先决条件。我们建议用前所未有的实验技术组合来阐明水中氢键的形成和断裂。氢键的断裂将由受控的激光激发来启动。氢键网络的后续演变将在分子水平上通过频闪方式(泵浦-探测方案)的X射线光谱学作为时间的函数进行监测。这将为氢键断裂和形成过程中短暂的早期阶段提供独特的途径，并有望极大地促进我们对水的理解。