Femtosecond studies of the influence of solvent on chemical reaction dynamics

在这个由化学部门实验物理化学项目资助的项目中，Bradforth将利用波长从215到300纳米的飞秒紫外泵浦探测光谱对液体溶液中的化学反应动力学进行研究。目的是表征溶剂如何通过笼化和能量耗散等动力学效应改变和控制嵌入的小分子溶质的反应性。该项目包括以下几个任务：1)开发CN、I和I*等平衡自由基的电子谱和重定向动力学的基准信息；2)研究了双电荷溴化铜阴离子和相关铜体系的电子抛射引起的溶质振动相干性；3)对ICN和BrCN进行光解研究，以探索键断裂的性质，从而了解碎片释放的大旋转能量最初是如何消散的。这项工作的目标是测试溶液动力学的基本理论，并为复杂介质中的反应提供分子图像。这项研究将与学生和博士后研究人员一起进行。

In this project, funded by the Experimental Physical Chemistry Program of the Chemistry Division, Bradforth will perform research on the chemical reaction dynamics in liquid solutions by means of femtosecond ultra violet pump-probe spectroscopy over the wavelength range from 215 to 300 nanometers. The objective is to characterize how solvents modify and control the reactivity of embedded small molecule solutes by dynamical effects such as caging and energy dissipation. The project consists of several tasks, including 1) development of benchmark information on the electronic spectra and reorientation dynamics of equilibrated radicals such as CN, I, and I*; 2) the investigation of solute vibrational coherences initiated by electron ejection via the charge-transfer-to-solvent detachment of the doubly-charged copper bromide anion and related copper systems; and 3) photodissociation studies of ICN and BrCN to explore the nature of bond breaking and thus how the large rotational energy release of the fragments is initially dissipated. The proposed work is directed toward the larger goal of testing fundamental theories of solution kinetics, and providing a molecular picture for reactions in complex media. This research will be conducted with students and postdoctoral research associates.