The intersystem crossing process of p-bromofluorobenzene studied with time-resolved photoelectron imaging
The intersystem crossing process of p-bromofluorobenzene studied with time-resolved photoelectron imaging
复制标题
时间分辨光电子成像研究对溴氟苯的系间窜越过程
DOI：
10.1063/1.3097184
复制
发表时间：
2009-04-14
影响因子：
4.4
通讯作者：
Zhang, Bing
中科院分区：
文献类型：
--
作者：
Cao, Zhenzhou;Wei, Zhengrong;Zhang, Bing
用飞秒时间分辨光电子成像光谱研究了对溴氟苯的超快过程。光电子图像显示有四个光电子环，分别位于0.39、0.86、1.13和1.61 eV。内环比外环的各向异性更强。分别记录了不同环的衰变轨迹。从图像中提取的清晰的光电子能量分布和不同的各向异性参数表明，在(1+1(‘))光子能量下与里德堡态发生共振。四种里德堡态的量子缺陷值分别为0.75、0.52、0.36，主量子数为3。S(1)(B(2))态的电子退相机制对应于从S(1)(B(2))态到T(1)(B(2))态的系间交叉和S(1)(B(2))态通过T(1)(B(1))态的预解离。S(1)(B(2))和T(1)(B(2))的寿命分别由光电子信号的衰变确定为40ps和33ps。前5ps随时间变化的各向异性参数表明对溴氟苯在S(1)(B(2))态的转动波相干性。
Ultrafast processes of p-bromofluorobenzene are studied with femtosecond time-resolved photoelectron imaging spectroscopy. The photoelectron image revealed four photoelectron rings centered at 0.39, 0.86, 1.13, and 1.61 eV, respectively. The inner rings are more anisotropic than the outer rings. The decay traces of the different rings were recorded separately. Sharp photoelectron energy distributions and different anisotropy parameters extracted from the images indicated resonances with Rydberg states at the (1+1(')) photon energy. The quantum defect values of the four Rydberg states were determined to be 0.75, 0.52, 0.36, and similar to 0, respectively, with principal quantum number of 3. The electron dephasing mechanism of the S(1)(B(2)) state corresponds to the intersystem crossing from the S(1)(B(2)) to T(1)(B(2)) state and the predissociation of the S(1)(B(2)) state via the T(1)(B(1)) state. The lifetimes of S(1)(B(2)) and T(1)(B(2)) are determined from the decay of the photoelectron signals to be 40 and 33 ps, respectively. The variety of time-dependent anisotropy parameters in the first 5 ps shows the rotational wave coherences of p-bromofluorobenzene at the S(1)(B(2)) state.