The intersystem crossing process of p-bromofluorobenzene studied with time-resolved photoelectron imaging.
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 approximately 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.
State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
Zhenzhou
Z
Cao
Zhengrong
Z
Wei
Linqiang
L
Hua
Changjin
C
Hu
Song
S
Zhang
Bing
B
Zhang