Department of Applied Physics and Chemistry and Institute for Laser Science, University of Electro-Communications, Chofugaoka, Chofu, Tokyo, Japan.
Chem Rec. 2011 Apr;11(2):99-116. doi: 10.1002/tcr.201000018. Epub 2011 Mar 4.
To gain a complete understanding of a chemical reaction, it is necessary to determine the structural changes that occur to the reacting molecules during the reaction. Chemists have long dreamed of being able to determine the molecular structure changes that occur during a chemical reaction, including the structures of transition states (TSs). The use of ultrafast spectroscopy to gain a detailed knowledge of chemical reactions (including their TSs) promises to be a revolutionary way to increase reaction efficiencies and enhance the reaction products, which is difficult to do using conventional methods that are based on trial and error. To confirm the molecular structures of TSs predicted by theoretical analysis, chemists have long desired to directly observe the TSs of chemical reactions. Direct observations have been realized by ultrafast spectroscopy using ultrashort laser pulses. Our group has been able to stably generate visible to near-infrared sub-5-fs laser pulses using a noncollinear optical parametric amplifier (NOPA). We used these sub-5-fs pulses to study reaction processes (including their TSs) by detecting structural changes. We determine reaction mechanisms by observing the TSs in a chemical reaction and by performing density-functional theory calculations.
要全面了解化学反应，就必须确定反应过程中反应物分子所发生的结构变化。长期以来，化学家们一直梦想能够确定化学反应过程中发生的分子结构变化，包括过渡态（TS）的结构。超快光谱学的应用有望为深入了解化学反应（包括其过渡态）提供一种革命性的方法，从而提高反应效率并增强反应产物，这是传统基于试错方法难以实现的。为了确认理论分析预测的 TS 分子结构，化学家们长期以来一直希望能够直接观察化学反应的 TS。超快光谱学使用超短激光脉冲实现了直接观察。我们的小组已经能够使用非共线光学参量放大器（NOPA）稳定地产生可见光到近红外的亚 5 飞秒激光脉冲。我们使用这些亚 5 飞秒脉冲通过检测结构变化来研究反应过程（包括其过渡态）。我们通过观察化学反应中的 TS 并进行密度泛函理论计算来确定反应机制。
