Vibrational Control of Bimolecular Reactions in Gases and Liquids

在化学部实验物理化学计划的这个项目中，CRIM将继续研究振动激发对双分子化学反应过程和速度的影响。目前的工作将把研究从气体扩展到液体，期望通过优先破坏选定的键来展示对双分子反应过程的选择性控制。在拟议的气相研究中，可见或红外光子将激发键的振动，然后这些键与光解产生的原子反应形成产物。测量产物的量子态有助于确定振动激发加速的反应路径。在有利的情况下，一个人可以优先割断一个键。液体和超临界流体中的振动驱动双分子反应需要试剂的超快激发和产物的检测。非线性光的产生将提供激发和吸收，或相干拉曼散射将用于检测。与理论家的合作将允许对动力学理论和势能面计算进行测试。在这项研究中，多原子分子和原子之间的化学反应的结果是通过激发键的分子振动来直接控制的，该键预计在反应过程中会断裂。这一预期是基于这样一个事实，即从反应物到产物发生的几何变化首先需要类似于分子振动期间发生的键的伸展。这项研究的结果预计将对大气化学、燃烧和对等离子体的理解产生影响。

In this project in the Experimental Physical Chemistry Program of the Chemistry Division, Crim will continue studies of the influence of vibrational excitation on the course and rate of bimolecular chemical reactions. The current work will extend the investigations from the gas into the liquid phase in the expectation of demonstrating selective control of the course of a bimolecular reaction by preferentially breaking a chosen bond. In the proposed gas-phase studies visible or infrared photons will excite vibrations of bonds which then react with photolytically created atoms to form products. Measuring the quantum states of the products helps identify the pathways of the reactions accelerated by the vibrational excitation. In favorable cases, one can cleave a bond preferentially. Vibrationally driven bimolecular reactions in liquids and supercritical fluids require ultrafast excitation of reagents and detection of products. Nonlinear light generation will provide the excitation and absorption or coherent Raman scattering will be used for detection. Collaborations with a theoretician will allow tests of dynamical theories and potential energy surface calculations. In this research the outcome of a chemical reaction between a polyatomic molecule and an atom is directly controlled by exciting the molecular vibration of the bond which is expected to break in the course of the reaction. This expectation is based on the fact that the geometry change that occurs in going from reactants to products first requires the stretching of bonds similar to that which occurs during molecular vibrations. The results of this research are expected to have an impact in atmospheric chemistry, combustion, and the understanding of plasmas