Dynamics of Electronically Excited States: Models for Chemical Reactivity

匹兹堡大学的David Pratt教授在实验物理化学项目的支持下，对分子束中的分子和溶剂化分子进行高分辨率电子光谱分析。高分辨率光谱提供了结构细节，揭示了低势垒分子内氢键、手性鉴定和气相溶剂重组的基本信息。本研究中提出的一些体系包括苯水和苯二聚体、对映体的弱结合配合物和扭曲的内部电荷转移分子。这些方法包括超声速膨胀、连续波分子束、倍频可调谐单频激光、空间选择性荧光检测和高速数据采集。在紫外线中获得接近1兆赫的无与伦比的分辨率。高分辨率光谱学可以为低分辨率光谱学实验中产生的争论提供“最终结论”，从而作为鉴定某些气相物质和配合物结构的基准测量。分子复合物的结合可以提供分子如何识别彼此的见解，并可以改进设计，例如，用于手性纯化药物的分离介质。电子光谱学是一个成熟的领域，然而，普拉特的工作类型在世界上只有几个小组进行。普拉特继续与美国规模较小的大学、工业和政府实验室以及国外大学的研究小组建立合作关系。

Professor David Pratt of the University of Pittsburgh is supported by the Experimental Physical Chemistry program to perform high resolution electronic spectroscopy on molecules and solvated molecules in molecular beams. The high resolution spectroscopy provides structural details that reveal fundamental information about low barrier intramolecular hydrogen bonds, chiral identification and solvent reorganization in the gas phase. Some of the systems proposed in this study include benzene-water and the benzene dimer, weakly bound complexes of enantiomers, and twisted internal charge transfer molecules. The methods include supersonic expansion, continuous wave molecular beams, frequency-doubled tunable single frequency lasers, spatially selective fluorescence detection and high speed data acquisition. Unparalleled resolution is obtained approaching 1 MHz in the ultraviolet.High resolution spectroscopy can provide the "final word" on debates that arise from low-resolution spectroscopy experiments, and thus serve as benchmark measurements for the identification of the structures some gas phase species and complexes. The bonding of molecular complexes can provide insight on how molecules recognize each other, and can improve the design, for example, of separation media for chiral purification of drugs. Electronic spectroscopy is a mature field, however, Pratt's type of work is only performed by several groups in the world. Pratt continues to build collaborative ties to research groups at smaller universities in the US, industrial and government labs, and at universities abroad.