Resonance Emission Studies of Intra- and Intermolecular Ultrafast Dynamics

在化学学部实验物理化学项目中，波士顿大学L. Ziegler教授将把先前对孤立分子超快动力学的研究扩展到凝聚相和团簇，以研究包埋液对分子激发态过程的影响。自发拉曼和荧光光散射技术将用于1)探测溶剂/镀液描述的时间尺度、振幅和运动特征，并确定这些自由度如何与电子激发耦合的微观细节，以及2)镀液相互作用如何影响这些发色团的准束缚激发态光分解的光化学动力学。将研究嵌入在团簇、溶液和高压气体中的表征良好的分子。将测量共振线形、退极化比和量子产率，以确定振动和旋转水平相关的消相和弛豫速率。化学反应通常需要将分子提升到激发态。由于分子在高压条件下、溶液中、嵌入固体基质或簇中的化学性质受到环境的影响，因此了解和理解这些变化对于改进基于化学反应的技术非常重要。本课题的研究将为嵌入在凝聚态介质中的表征良好的分子的反应动力学和动力学提供数据基础和理论模型。＊＊＊

9316148 Ziegler In this project of the Experimental Physical Chemistry Program in the Chemistry Divison, Prof. L. Ziegler of Boston University will extend previous studies of ultrafast dynamics in isolated molecules to the condensed phase and clusters, so as to study the effects of the embedding bath on processes in the excited electronic state of the molecule. Spontaneous Raman and fluorescence light scattering techniques will be used to 1) probe the time scales, amplitudes and motional character of solvent/bath descriptions and to determine microscopic details of how these degrees of freedom couple to electronic excita- tions, and 2) how the bath interactions affect the photo- chemical dynamics of the quasi-bound excited state photodisso- ciation of these chromophores. Well characterized molecules embedded in clusters, solutions, and high pressure gases will be investigated. Resonance lineshapes, depolarization ratios, and quantum yields will be measured to determine the vibrational and rotational level dependent dephasing and relaxation rates. 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. ***