Champenois Elio G, Shivaram Niranjan H, Wright Travis W, Yang Chan-Shan, Belkacem Ali, Cryan James P
Graduate Group in Applied Science and Technology, University of California, Berkeley, California 94720, USA.
Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
J Chem Phys. 2016 Jan 7;144(1):014303. doi: 10.1063/1.4939220.
We present a measurement of the time-resolved photoelectron kinetic energy spectrum of ethylene using 156 nm and 260 nm laser pulses. The 156 nm pulse first excites ethylene to the (1)B1u (ππ(∗)) electronic state where 260 nm light photoionizes the system to probe the relaxation dynamics with sub-30 fs resolution. Recent ab initio calculations by Mori et al. [J. Phys. Chem. A 116, 2808-2818 (2012)] have predicted an ultrafast population transfer from the initially excited state to a low-lying Rydberg state during the relaxation of photoexcited ethylene. The measured photoelectron kinetic energy spectrum reveals wave packet motion on the valence state and shows indications that the low-lying π3s Rydberg state is indeed transiently populated via internal conversion following excitation to the ππ(∗) state, supporting the theoretical predictions.
我们展示了使用156纳米和260纳米激光脉冲对乙烯的时间分辨光电子动能谱的测量。156纳米脉冲首先将乙烯激发到(1)B1u(ππ(∗))电子态，在此260纳米光将系统光离子化，以亚30飞秒的分辨率探测弛豫动力学。Mori等人[《物理化学杂志A》116, 2808 - 2818(2012)]最近的从头算计算预测，在光激发乙烯的弛豫过程中，会有超快的布居从初始激发态转移到低能里德堡态。所测量的光电子动能谱揭示了价态上的波包运动，并表明在激发到ππ(∗)态后，低能π3s里德堡态确实通过内转换短暂布居，这支持了理论预测。
