Oesterling Sven, Schalk Oliver, Geng Ting, Thomas Richard D, Hansson Tony, de Vivie-Riedle Regina
Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany.
Department of Physics, Stockholm University, AlbaNova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden.
Phys Chem Chem Phys. 2017 Jan 18;19(3):2025-2035. doi: 10.1039/c6cp06240g.
For the series furan, furfural and β-furfural we investigated the effect of substituents and their positioning on the photoinduced relaxation dynamics in a combined theoretical and experimental approach. Using time resolved photoelectron spectroscopy with a high intensity probe pulse, we can, for the first time, follow the whole deactivation process of furan through a two photon probe signal. Using the extended 2-electron 2-orbital model [Nenov et al., J. Chem. Phys., 2011, 135, 034304] we explain the formation of one central conical intersection and predict the influence of the aldehyde group of the derivatives on its geometry. This, as well as the relaxation mechanisms from photoexcitation to the final outcome was investigated using a variety of theoretical methods. Complete active space self consistent field was used for on-the-fly calculations while complete active space perturbation theory and coupled cluster theory were used to accurately describe critical configurations. Experiment and theory show the relaxation dynamics of furfural and β-furfural to be slowed down, and together they disclose an additional deactivation pathway, which is attributed to the n lonepair state introduced with the aldehyde group.
对于呋喃、糠醛和β-糠醛系列，我们采用理论与实验相结合的方法，研究了取代基及其位置对光诱导弛豫动力学的影响。通过使用高强度探测脉冲的时间分辨光电子能谱，我们首次能够通过双光子探测信号追踪呋喃的整个失活过程。利用扩展的双电子双轨道模型[涅诺夫等人，《化学物理杂志》，2011年，135卷，034304]，我们解释了一个中心锥形交叉点的形成，并预测了衍生物中醛基对其几何结构的影响。我们使用多种理论方法研究了从光激发到最终结果的弛豫机制。完全活性空间自洽场用于即时计算，而完全活性空间微扰理论和耦合簇理论用于精确描述关键构型。实验和理论表明，糠醛和β-糠醛的弛豫动力学减慢，并且它们共同揭示了一条额外的失活途径，这归因于醛基引入的n孤对态。
