Liu Yuzhu, Gerber Thomas, Sych Yaroslav, Radi Peter, Knopp Gregor
Paul Scherrer Institute, 5232 Villigen, Switzerland.
Opt Express. 2013 Jul 15;21(14):16639-47. doi: 10.1364/OE.21.016639.
The ultrafast dynamics of the second singlet electronically excited state (S) in ethylbenzene has been studied by femtosecond time-resolved photoelectron imaging. The time evolution of the photoelectron signal can be well described by a biexponential decay: a rapid relaxation pathway with a time constant of 60 ( ± 9) fs and a longer-lived channel on a timescale of 2.58 ( ± 0.22) ps. The rapid relaxation is ascribed to the ultrafast internal conversion from the S state to the vibrationally hot S state. This internal conversion process has been observed in real time. The slow photoelectron signal reflects the depopulation of secondarily populated high vibronic S state.
通过飞秒时间分辨光电子成像技术研究了乙苯中第二单重电子激发态（S₂）的超快动力学。光电子信号的时间演化可以用双指数衰减很好地描述：一个时间常数为60（±9）飞秒的快速弛豫途径和一个在2.58（±0.22）皮秒时间尺度上寿命较长的通道。快速弛豫归因于从S₂态到振动激发的S₁态的超快内转换。这个内转换过程已被实时观测到。缓慢的光电子信号反映了二次填充的高振动态S₁态的布居数减少。
