Development of a 2D Microwave Spectrometer

在主要研究仪器（MRI）和化学研究仪器和设施（CRIF）项目的支持下，弗吉尼亚大学的Brooks H. Pate教授将开发一种最先进的激光二维微波光谱仪。这将引入时域分子旋转光谱作为一种研究化学反应动力学的新技术。化学反应被描述为不同局域结构之间的人口转移。例如，反应可以在不同的电子态之间进行，其中反应物和生成物的电子构型是不同的。分子异构化反应可以类似地描述为分子核构型的变化。反应的一个共同特征是分子结构在反应构型上通常是不同的。对于异构化反应，这个结果是很明显的。对于不同电子态之间的反应，通常由于两种电子构型成键的不同而引起结构变化。在化学反应中，惯性矩是随时间变化的量。因此，反应动力学可以通过测量旋转光谱的时间演化来确定。分子光谱学这一新领域的成功发展将使揭示涉及多种异构体的复杂反应的反应途径成为可能。

With support from the Major Research Instrumentation (MRI) and the Chemistry Research Instrumentation and Facilities (CRIF) Programs, Prof. Brooks H. Pate of the University of Virginia will develop a state-of-the-art laser 2D microwave spectrometer. This will introduce time-domain molecular rotational spectroscopy as a new technique to study chemical reaction dynamics. Chemical reactions are described as population transfer between different localized structures. For example, the reaction can take place between different electronic states where the electronic configuration is different for the reactant and product. Molecular isomerization reactions can similarly be described as changes in the nuclear configuration of the molecule. One common feature of reactions is that the molecular structure is usually different in the reacting configurations. For isomerization reactions, this result is readily apparent. For reactions between different electronic states, there is often a structural change caused by the different bonding of the two electronic configurations. During the chemical reaction the moments-of-intertia are time-dependent quantities. The reaction kinetics can, therefore, be determined by measuring the time evolution of the rotational spectrum. The successful development of this new field of molecular spectroscopy will make it possible to unravel reaction pathways for complex reactions involving several isomers.