Structural Kinetics, a Novel Tool Using Gas Electron Diffraction With a Pulsed Electron Beam Synchronous With Photoexcitation

在这个项目中的物理化学计划的化学 司，教授J。尤班克和L。化学系的谢弗 阿肯色州大学将继续发展， 实时气体电子衍射（GED）的应用，使用脉冲 与光激发同步的电子束。 这项技术将是 主要应用于研究的构象和结构的 短寿命的化学物种，即那些在高激发电子 结构和构象与之显着不同的状态 那些处于基态和低激发态的物种， 由于单分子反应而产生的动力学变化。 传统的GED依赖于使用照相底片来记录 并存储由电子衍射产生的信息， 分子。 因此，这种方法仅限于研究结构 稳定的分子。 当前分子动力学的研究关注 分子系统的结构和构象 在反应过程中发生变化。 实验信息关于这样的 过程只能通过技术手段获得，其中时间 起着至关重要的作用。 皮科和飞秒的方法 光谱学在这方面已经非常成功，但也有其 由于口译困难而造成的限制， 复杂的光谱模式 实时GED方法是由 主要研究人员在使重要的 对理解短寿命的 物种 该项目的目的是利用这一潜力， 有助于我们理解分子生物学的基本方面， 动力学

In this project in the Physical Chemistry Program of the Chemistry Division, Professors J. Ewbank and L. Schafer of the Chemistry Department of the University of Arkansas will continue the development and application of real-time gas electron diffraction (GED) using a pulsed electron beam synchronous with photoexcitation. The technique will be applied primarily to the study of the conformation and structure of short-lived chemical species, namely those in highly excited electronic states where the structure and conformation differ significantly from those in the ground and low-lying excited states, or species undergoing dynamical changes as the result of unimolecular reactions. Traditional GED has relied on the use of the photographic plate to record and store the information generated by the diffraction of electrons by molecules. This method was therefore limited to studying the structures of stable molecules. Current research in molecular dynamics concerns itself with how the structure and conformation of a molecular system evolves during a reaction process. Experimental information about such processes can only be obtained by means of techniques in which the time plays an essential role. The methods of pico- and femtosecond spectroscopy have been very successful in this regard but also have their limitations owing to the difficulty in interpreting often extremely complex spectral patterns. The method of real-time GED developed by the principal investigators has shown great promise in making important contribution to the understanding of the properties of short-lived species. The aim of this project is to capitalize on this potential and contribute to our understanding of the basic aspects of molecular dynamics.