Linear and Nonlinear Spectroscopy of Unimolecular Dynamics

在这个由化学部实验物理化学计划支持的项目中，耶鲁大学的帕特里克瓦卡罗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。 早期的工作单分子转换S2O和分子内氢键和质子转移的丙二醛将被扩展，结构单分子转换氰家庭将被详细检查，和异构体之间的转换氰家庭，CNNC，CNCN，CNNC将被研究。 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）技术将被开发和量化，包括腔衰荡光谱（CRDS）。 拟议的活动将促进对单分子动力学的认识和理解，以及对来自线性和非线性光学测量的信号的解释。 在这个项目中进行的调查将有助于增加分子行为的理解，在各种化学和生物过程中发挥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路线来获得所需的产品。 分子的结构偏好的知识与键，可以自由旋转的影响理解蛋白质折叠的生物学重要性的分子。

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.