Linear and Nonlinear Spectroscopy of Unimolecular Dynamics

耶鲁大学的Patrick Vaccaro将利用各种线性和非线性光谱技术研究几种中小分子的单分子反应动力学，该项目由化学学部实验物理化学项目资助。在S2O中单分子转化和丙二醛中分子内氢键和质子转移的早期工作将得到扩展，将详细研究氰族的结构单分子转化，并研究氰族同分异构体与CNNC、CNCN和CNNC之间的转化。实验结果将与使用新理论方法的计算结果进行比较。各种简并四波混频（DFWM）技术将得到发展和量化，包括空腔衰荡光谱（CRDS）。拟议的活动将促进对单分子动力学的认识和理解，以及对线性和非线性光学测量产生的信号的解释。在这个项目中进行的调查将有助于增加对分子行为的理解，分子行为在各种化学和生物过程中起着基本和重要的作用。例如，可以阐明化学合成过程中发生的键重组事件的顺序，使化学家能够设计出更有效的途径来获得所需的产品。对具有自由旋转键的分子的结构偏好的了解影响了对具有生物学重要性的分子中蛋白质折叠的理解。

In this project supported by the Experimental Physical Chemistry Program of the Chemistry Division, Patrick Vaccaro of Yale University will study the unimolecular reaction dynamics of several small to medium-sized molecules using a variety of linear and nonlinear spectroscopic techniques. Earlier work on unimolecular transformations in S2O and on intramolecular hydrogen bonding and proton transfer in malonaldehyde will be extended, the structure unimolecular transformations in the cyanogen family will be examined in detail, and transformations between isomers in the cyanogen family, CNNC, CNCN, and CNNC will be studied. Experimental findings will be compared to calculations using new theoretical methods. Various degenerate four-wave mixing (DFWM) techniques will be developed and quantified, including Cavity Ring-Down Spectroscopy (CRDS). The proposed activities will advance the knowledge and the understanding of unimolecular dynamics and the interpretation of signals derived from linear and nonlinear optical measurements. The investigations undertaken in this project will help increase understanding of molecular behavior that plays a basic and important role in a variety of chemical and biological processes. For example, the sequence of bond reorganization events that occur during chemical syntheses can be elucidated, allowing chemists to devise more efficient routes to a desired product. The knowledge of structural preferences of molecules with bonds that can freely rotate impacts the understanding of protein folding in molecules of biological importance.