Unimolecular Reaction Dynamics

这项工作的目的是了解小分子基电子态的单分子反应动力学，从而了解它们的热单分子反应。将进行三种实验：1)以足够的振动能量激活分子的红外光谱，2)直接测量每秒100万到1000亿的离解率，3)测量产物能态和角动量分布，以及它们与被激活分子初始量子态的标量和矢量关联。将特别强调两个性质不同的原型分子--甲酰氟和乙烯酮。化学反应动力学站在当代物理化学研究的前沿。这些研究的主要目的是获得对反应过程的能量学和动力学的详细的、分子水平的了解。这涉及到在确定的电子、振动和旋转量子状态下制备分子，不仅观察反应的产物，而且观察总能量和角动量如何在母分子解离成碎片时在各种可能的反应通道中重新分配。与只能通过温度和压力的变化来粗略地控制化学反应并遵循所有可能的反应通道的传统方法相比，对反应动力学的详细的、分子水平的了解提供了密切控制反应的可能性，从而最大化地产生所需的反应产物的效率。本研究将提供关键数据，以测试和进一步发展化学反应动力学和动力学各个方面的最先进理论模型。

The goal of this work is to understand the unimolecular reaction dynamics of the ground electronic states of small molecules and hence of their thermal unimolecular reactions. Three kinds of experiments will be conducted: 1) infrared spectroscopy of molecules activated with sufficient vibrational energy to dissociate, 2) direct measurement of dissociation rates in the range from 1 million to 100 billion per second, and 3) measurement of product energy state and angular momentum distributions and their scalar and vector correlations as a function of the initial quantum state of the activated molecule. Special emphasis will be given to two qualitatively different, prototype molecules- formyl fluoride and ketene. The dynamics of chemical reactions stands at the forefront of investigations in contemporary physical chemistry. The primary purpose of these investigations is to obtain a detailed, molecular level understanding of the energetics and dynamics of reaction processes. This involves the preparation of a molecule in defined electronic, vibrational, and rotational quantum states and observing not only the products of a reaction, but also how the total energy and angular momentum redistribute themselves among the various possible reaction channels followed by the parent molecule as it dissociates into fragments. In contrast to conventional methods in which chemical reactions can be only crudely controlled through variations of temperature and pressure, and in which all possible reaction channels are followed, a detailed, molecular level understanding of the reaction dynamics offers the possibility of close control of a reaction and thereby maximizing the efficiency of producing the desired reaction products. The present research will provide critical data which will allow the testing and further development of state-of-the-art theoretical models for various aspects of chemical reaction kinetics and dynamics.