Ultrafast Dynamics Through Conical Intersections in 2,6-dimethylpyridine Studied with Time-resolved Photoelectron Imaging
- Received Date: 2011-08-02
- 2,6-dimethylpyridine, Photoelectron imaging, Conical intersection, Internal conversion, Time-resolved spectroscopy
Abstract: The ultrafast dynamics through conical intersections in 2,6-dimethylpyridine has been stud-ied by femtosecond time-resolved photoelectron imaging coupled with time-resolved mass spectroscopy. Upon absorption of 266 nm pump laser, 2,6-dimethylpyridine is excited to the S2 state with a ππ* character from S0state. The time evolution of the parent ion sig-nals consists of two exponential decays. One is a fast component on a timescale of 635 fs and the other is a slow component with a timescale of 4.37 ps. Time-dependent photo-electron angular distributions and energy-resolved photoelectron spectroscopy are extracted from time-resolved photoelectron imaging and provide the evolutive information of S2 state. In brief, the ultrafast component is a population transfer from S2 to S1 through the S2/S1 conical intersections, the slow component is attributed to simultaneous IC from the S2 state and the higher vibrational levels of S1 state to S0 state, which involves the coupling of S2/S0 and S1/S0 conical intersections. Additionally, the observed ultrafast S2→S1 transition occurs only with an 18% branching ratio.
|Citation:||Xue-jun Qiu, Rong-shu Zhu, Yan-qi Xu, Abulimiti Bumaliya, Song Zhang, Bing Zhang. Ultrafast Dynamics Through Conical Intersections in 2,6-dimethylpyridine Studied with Time-resolved Photoelectron Imaging[J]. Chinese Journal of Chemical Physics , 2011, 24(5): 551-556. doi: 10.1088/1674-0068/24/05/551-556|