Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom.
J Phys Chem A. 2010 Jan 14;114(1):68-72. doi: 10.1021/jp908195k.
Recent spectroscopic measurements have shown that following excitation of indole molecules above the (1)pipi*-(1)pisigma* conical intersection, photoinduced N-H bond cleavage results in a range of H-atom kinetic energy release. H-atoms with large amounts of kinetic energy were attributed to direct dissociation whereas those with low kinetic energy were attributed to indirect pathways such as statistical unimolecular decay. With use of a combination of femtosecond pump-probe spectroscopy and velocity map ion-imaging techniques, both energy and time-resolved photoinduced H-atom elimination at 200 nm has been measured. The results show that H-atoms with both high and low kinetic energies are generated on an ultrafast time scale, <200 fs, suggesting that on the time frame of our measurements (<200 ps) there appears to be a direct route to H-atom formation yielding H-atoms with low kinetic energies.
最近的光谱测量表明，在吲哚分子被激发到（1）pipi*-（1）pisigma*锥形交叉点以上后，光诱导的 N-H 键断裂导致一系列 H 原子的动能释放。具有大量动能的 H 原子归因于直接解离，而具有低动能的 H 原子归因于间接途径，如统计单分子衰变。使用飞秒泵浦-探针光谱学和速度图离子成像技术的组合，在 200nm 处测量了能量和时间分辨的光诱导 H 原子消除。结果表明，在超快时间尺度（<200fs）下，既生成了具有高动能的 H 原子，也生成了具有低动能的 H 原子，这表明在我们的测量时间框架（<200ps）内，似乎存在一条直接的 H 原子形成途径，生成具有低动能的 H 原子。
