Photophysics and Photochemistry of Gas Phase Organic Compounds and Biomolecules Studied Using Orientation via Uniform Electric Fields

俄勒冈州立大学的孔伟获得了实验物理化学项目的资助，她利用激光诱导荧光和共振增强多光子电离将场取向分子的光谱研究扩展到中等大小的有机分子和生物相关物种。具体来说，我们建议研究硝基苯和硝基甲苯异构体的电位表面：(1)确定参与电子跃迁的物质的对称性；(2)观察光解动力学；(3)评估甲基取代的影响；(4)研究邻位效应，如邻硝基甲苯的分子内氢提取。这些研究之后，将观察核酸碱基及其甲基衍生物的激发概率，以确定这些取代的影响。这些研究将导致对有机化合物和生物相关物种与光的相互作用的细节有更深入的基本理解，通过选择性地根据光的偏振取向分子。这项工作已应用于生物物理学，该方法可以潜在地应用于研究紫外线诱导DNA损伤的机制以及利用紫外线激活抗肿瘤药物。

Wei Kong of Oregon State University is supported by a grant from the Experimental Physical Chemistry Program to extend her studies of the spectroscopy of field oriented molecules to medium sized organic molecules and biologically relevant species using laser induced fluorescence and resonance enhanced multiphoton ionization. Specifically, it is proposed to investigate the potental surfaces of nitrobenzene and the nitrotoluene isomers to: (1) identify the symmetry of the species involved in the electronic transitions; (2) observe the photodissociation dynamics; (3) assess the effects of methyl substitution and (4) investigate ortho effects such as intramolecular hydrogen abstraction in o-nitrotoluene. These studies will be followed by observations of the excitation probabilities of nucleic acid bases and their methyl derivatives to determine the effects of these substitutions.The studies will lead to a deeper fundamental understanding of the details of the interaction of organic compounds and biologically relevant species with light by selectively orienting the molecules with respect to the polarization of that light. The work has application to biophysics and the methods can potentially be applied to study the mechanisms involved in inducing lesions in DNA by ultraviolet light and in the use of this light to activate antitumor drugs.