Acta Phys. -Chim. Sin. ›› 2015, Vol. 31 ›› Issue (9): 1655-1661.doi: 10.3866/PKU.WHXB201506291


Dynamics of Excited o-Dichlorobenzene

Xiao-Ying. LI1,Li. WANG2,*(),Yan-Qiu. WANG3,Zhe. SONG1,Ben-Kang. LIU3,*()   

  1. 1 School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029, Liaoning Province, P. R. China
    2 College of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600, Liaoning Province, P. R. China
    3 State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning Province, P. R. China
  • Received:2015-04-07 Published:2015-09-06
  • Contact: Li. WANG,Ben-Kang. LIU;
  • Supported by:
    the National Natural Science Foundation of China(21303199)


The dynamics of the first excited singlet electronic state (S1) of o-dichlorobenzene was investigated in real time by the femtosecond pump-probe method combined with time-of-flight mass spectroscopy and the photoelectron velocity mapping technique. The lifetime of the S1 vibrational ground state was determined experimentally to be (651 ± 10) ps, corresponding to the intersystem crossing process from the S1 state to the triplet state. Two decay channels were found in the S1 vibrationally excited mode 9a218a2. The fast process (lifetime constant (458 ± 12) fs) is because of the internal conversion from the S1 vibrationally excited mode to the highly vibrationally excited ground state (S0). The slow process (lifetime constant (90 ± 10) ps) is attributed to the intersystem crossing process from the S1 state to the triplet state (T1). Photoelectrons with long lifetime characteristics in the spectrum might be connected with the intersystem crossing process. Enhanced spinorbital coupling in the S1 highly vibrationally excited state accelerates the intersystem crossing process.

Key words: o-Dichlorobenzene, Vibrational excitation, Photoelectron imaging, Photoelectron kinetic energy spectrum