Femtosecond Studies of Chemical Reaction Dynamics in Simple Liquids

查尔斯·哈里斯得到了理论和计算化学计划的资助，继续他在简单液体中化学反应动力学的飞秒研究。研究的主线有两条。研究的第一条线包括利用飞秒和皮秒红外和可见光激光实验以及分子动力学模拟研究多原子分子在溶液中的溶质/溶剂相互作用。这项工作将把已经完成的关于液氪和氙气中碘的工作扩展到双原子分子，如液氪和氙气中的双原子碘阴离子、氯化碘和溴化碘。红外泵浦和探测技术也将被用来研究简单多原子在氪和氙溶剂中的碳氢伸缩模弛豫时间随压力的变化。第二个研究领域涉及利用飞秒和皮秒红外和可见光光谱技术研究几种有机金属化合物的反应机理，这些化合物的支化比和量子产率受溶质和溶剂之间的超快能量转移控制。这些研究将包括广泛的机理研究，包括过渡金属化合物中碳-氢和硅-氢键的激活以及芳香族配体的光化学环滑移。由于许多商业上重要的化学反应都是在溶剂中进行的，因此了解这些溶剂对反应动力学的影响是很重要的。许多效应，如溶剂笼效应、振动弛豫和量子力学隧道效应，在气相中不存在，完全主导了凝聚相化学反应。重要的是开发可靠的化学体系模型理论，然后将其应用于提高具有重要商业意义的化学反应的效率。哈里斯正在进行的工作为这些理论的发展提供了重要的实验基础。

Charles Harris is supported by a grant from the Theoretical and Computational Chemistry Program to continue his research in femtosecond studies of chemical reaction dynamics in simple liquids. Two main lines of research will be pursued. The first line of research involves the investigation of solute/solvent interactions of polyatomic molecules in solution using femtosecond and picosecond infrared and visible laser experiments as well as molecular dynamics simulations. This work will extend the work already completed on iodine in liquid krypton and xenon to diatomic molecules such as diatomic iodine anion, iodine chloride and iodine bromide in liquid krypton and xenon. Infrared pump and probe techniques will also be used to examine carbon-hydrogen stretching mode relaxation times of simple polyatomic as a function of pressure in krypton and xenon solvents. The second area of study involves the use of femtosecond and picosecond infrared and visible spectroscopic techniques to study reaction mechanisms of several organometallic compounds whose branching ratios and quantum yields are controlled by the ultrafast energy transfer between solute and solvent. These studies will encompass a broad range of mechanistic studies, including carbon-hydrogen and silicon-hydrogen bond activation in transition metal compounds and photochemical ring slippage of an aromatic ligand. Since many commercially important chemical reactions take place in solvents, it is important to understand the influence that such solvents have on the reaction dynamics. A number of effects, such as solvent cage effects, vibrational relaxation and quantum mechanical tunneling, that are not present in the gas phase, completely dominate condensed phase chemical reactions. It is important to develop reliable theories for model chemical systems that can then be applied to improving the efficiency of commercially important chemical reactions. The work that is being performed by Harris provides an important experimental basis for the development of such theories.