Time and Frequency Domain Studies of Ultrafast Dynamics in Liquids and Solutions

液体和溶液中超快动力学的时域和频域研究

• 批准号: 9712725
• 负责人: Lawrence Ziegler
• 金额: --
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2001-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9712725&HistoricalAwards=false
• 关键词: Time; Frequency; Domain; Studies; Ultrafast

In this project of the Experimental Physical Chemistry Program in the Chemistry Division with support for instrumentation from the Office of Multidisciplinary Activities, Prof. L. Ziegler of Boston University will perform time-domain and spontaneous emission frequency-domain studies on ultrafast dynamics of solutions and neat liquids. The spontaneous resonance emission of short-lived photodissociative molecules in high-pressure gases (approaching liquid densities), liquids, and supercritical phases will be analyzed as a probe of time scales of solvation, optical dephasing and bath-induced nonadiabatic effects. Classical Molecular Dynamics simulation and instantaneous normal mode techniques will be used to analyze the experimental observations. Two extensions of femtosecond polarization spectroscopy, dispersed optical heterodyne detected (OHD) birefringence and dichroism of transparent liquids, will be developed. The role of two-photon absorption resonances in femtosecond pump-probe spectroscopy will be explored. Chemical reactions usually require the elevation of molecules to excited states of energy. Since the chemistry of molecules under conditions of high pressure, in solution, or embedded in a solid matrix or in a cluster is affected by their environment, it is important to know and understand these changes in order improve the technology based on chemical reactions. The research undertaken in this project will provide a data base and theoretical model for the reaction kinetics and dynamics of well characterized molecules which are embedded in a condensed phase medium. It also helps in the understanding of the outcome of many types of light-initiated chemical events.

在化学分部实验物理化学计划的这个项目中，多学科活动办公室支持仪器，波士顿大学的L. Ziegler教授将对解决方案和纯净液体的超快动力学进行时间域和自发发射频率域研究。高压气体（接近液体密度），液体和超临界阶段中短寿命热共生分子的自发共振发射将被分析，以探测溶剂化的时间尺度，光学脱发和浴浴诱导的非放光性效应。经典的分子动力学模拟和瞬时正常模式技术将用于分析实验观测。将开发两种飞秒极化光谱的延伸，分散的光学杂作（OHD）双发性杂物和透明液体的二分法。将探索两光子吸收共振在飞秒泵探针光谱中的作用。化学反应通常需要分子升高到激发能量态。由于在高压条件下，溶液或嵌入固体基质或集群中的分子化学性质受其环境的影响，因此了解和理解这些变化以改善基于化学反应的技术很重要。该项目中进行的研究将为嵌入在冷凝相培养基中的良好特征分子的反应动力学和动力学提供数据库和理论模型。它还有助于理解许多类型的光发射化学事件的结果。