Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (04): 965-970.doi: 10.3866/PKU.WHXB20110404

• PHOTOCHEMISTRY AND RADIATION CHEMISTRY • Previous Articles     Next Articles

Ultrafast Dynamics of the First Excited State of Chlorobenzene

LIU Yu-Zhu, QIN Chao-Chao, ZHANG Song, WANG Yan-Mei, ZHANG Bing   

  1. State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China; Graduate University of Chinese Academy of Sciences, Beijing 100049, P. R. China
  • Received:2010-12-16 Revised:2011-01-21 Published:2011-03-29
  • Contact: ZHANG Bing E-mail:bzhang@wipm.ac.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20973194) and Innovation Foundation of Chinese Academy of Sciences (KJCX1-YW-N30).

Abstract:

Ultrafast dynamics of the first excited state (S1) of chlorobenzene was studied using a combination of femtosecond time-resolved photoelectron imaging and time-resolved mass spectroscopy. One-photon absorption at 266.7 nm was used to populate the S1 state of chlorobenzene. The time evolution of the parent ion signals consists of different biexponential decays. One is a fast component on a timescale of (152±3) fs and the other is a slow component with a timescale of (749±21) ps. Time- resolved electron kinetic energies (eKE) and time-resolved photoelectron angular distributions (PADs) were extracted from time-resolved photoelectron imaging and are discussed in detail. The ultrafast process with a time constant of (152±3) fs is a population transfer within the S1 state, and only a vibrational energy transfer process with strong coupling is a reasonable explanation. This is attributed to an ultrafast process of dissipative intramolecular vibrational energy redistribution (IVR). The lifetime of the S1 state was determined to be (749±21) ps, and its deactivation was due to slow internal conversion to the ground state. Additionally, nonadiabatic alignment and rotational dephasing of the S1 state of chlorobenzene, as a typical asymmetric top molecule, were observed. The first C-type and J-type recurrences are expected at delay time of 205.8 and 359.3 ps, respectively.

Key words: Photoelectron image, Ultrafast process, Vibrational energy redistribution, Chlorobenzene, Nonadiabatic alignment

MSC2000: 

  • O644