Ultrafast Vibrational Dynamics of Water and Water in Confinement

水和约束水的超快振动动力学

• 批准号: 0504038
• 负责人: Dana Dlott
• 金额: --
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-11-01 至 2009-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0504038&HistoricalAwards=false
• 关键词: Ultrafast; Vibrational; Dynamics; Water; Confinement

This award by the Solid State Chemistry program in the Division of Materials Research to University of Illinois Urbana-Champaign is to probe fast small-amplitude structural dynamics of water and water in confined spaces using femtosecond infrared and visible laser pulses. All biological systems and many materials contain confined water in tiny pockets of just a few aggregated water molecules. With this award, Professor Dlott will study water trapped inside molecular nanostructures such as reverse micelles and on the surfaces of biological molecules and nanoparticles. An OH stretch excited by a femtosecond pulse is sensitive during its lifetime to spontaneous changes, if the local hydrogen bondings work. When the excitation decays, it is possible to detect molecular groups that receive the energy, and to identify the structure and composition of the confining media. For large-amplitude motions, the PI has developed a unique method using a femtosecond laser-driven shock wave to disrupt the confined water structure. This disruption and spontaneous self-repair can be probed by femtosecond vibrational spectroscopy. A better understanding of confined water will broadly advance the state of knowledge of disciplines from agriculture to zoology, and is needed to understand factors that govern self-assembly of materials and biomolecular dynamics.At present, molecular motions that underlie water's unique properties are not fully understood, especially water in confined spaces. Using a unique femtosecond laser apparatus developed by the PI, fast small-amplitude changes in the hydrogen bonding structure of confined water trapped inside or on the surface of molecular nanostructures can be measured. Sometimes confined water is involved in fast large-scale molecular transformations that completely disrupt its structure. These transformations are difficult to study with conventional techniques. Hence, the PI is developing a method that uses a tiny explosion generated by a femtosecond laser pulse to disrupt the structure of a sheet of confined water of few molecular thick. This disruption and spontaneous self-repair can then be probed by laser spectroscopy. A better understanding of confined water will broadly advance the state of knowledge of different disciplines, and is needed to understand factors that govern self-assembly of materials and biomolecular dynamics. Students and postdoctoral candidates will be trained to be effective problem-solvers, preparing them for future success in a wide range of disciplines. Technologies being developed for high-speed laser spectroscopy will be shared with scientists and engineers at other universities, national laboratories and industries, and would lead to improved products for imaging science and lithography.

该奖项由伊利诺伊大学厄巴纳-香槟分校材料研究部固体化学项目授予，旨在利用飞秒红外和可见激光脉冲探测密闭空间中水和水的快速小振幅结构动力学。所有的生物系统和许多材料都在由几个聚集的水分子组成的小口袋中包含了封闭的水。有了这个奖项，Dlott教授将研究分子纳米结构（如反胶束）和生物分子和纳米颗粒表面上的水。如果局部氢键起作用，由飞秒脉冲激发的OH拉伸在其生命周期内对自发变化很敏感。当激发衰减时，就有可能检测到接受能量的分子群，并确定约束介质的结构和组成。对于大振幅运动，PI开发了一种独特的方法，使用飞秒激光驱动的冲击波来破坏承压水结构。这种破坏和自发的自我修复可以用飞秒振动光谱来探测。更好地了解密闭水将广泛地推进从农业到动物学等学科的知识状态，并且需要了解控制材料自组装和生物分子动力学的因素。目前，人们还没有完全了解水的独特性质背后的分子运动，尤其是密闭空间中的水。利用PI开发的一种独特的飞秒激光装置，可以测量分子纳米结构内部或表面的封闭水的氢键结构的快速小幅度变化。有时，封闭水参与了快速的大规模分子转化，完全破坏了其结构。这些变换很难用常规技术来研究。因此，PI正在开发一种方法，利用飞秒激光脉冲产生的微小爆炸来破坏几个分子厚的密闭水片的结构。这种破坏和自发的自我修复可以用激光光谱学来探测。更好地了解承压水将广泛地推进不同学科的知识状态，并且需要了解控制材料自组装和生物分子动力学的因素。学生和博士后候选人将被训练成有效的问题解决者，为他们将来在广泛的学科领域取得成功做好准备。正在开发的高速激光光谱学技术将与其他大学、国家实验室和行业的科学家和工程师共享，并将改进成像科学和光刻技术的产品。