Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (05): 1045-1053.doi: 10.3866/PKU.WHXB201203061


Vibrational Internal Energy of Chloromethyl Radical Formed by the Photodissociation of CH2BrCl at 265 nm

ZHANG Xiu1, WU Dong2, TANG Bi-Feng1   

  1. 1. Department of Physics, Hubei Engineering University, Xiaogan 432000, Hubei Province, P. R. China;
    2. School of Physical Science and Technology, Huazhong Normal University, Wuhan 430079, P. R. China
  • Received:2011-12-21 Revised:2012-03-05 Published:2012-04-26
  • Contact: TANG Bi-Feng
  • Supported by:

    The project was supported by the Science Foundation of the Education Department of Hubei Province, China (Z20082601).

Abstract: Photodissociation of CH2BrCl was investigated around 265 nm using resonance-enhanced multiphoton ionization technique combined with velocity map ion-imaging detection. The ion images of Br (2P1/2) and Br (2P3/2) were analyzed to obtain the corresponding velocity distributions and total translational energy distributions. Using an impulsive model invoking angular momentum conservation, the vibrational internal energy distributions of chloromethyl radical (·CH2Cl) formed by the photodissociation of CH2BrCl, were derived from the total translational energy distributions. In the CH2BrCl+hv→Br (2P1/2)+CH2Cl channel, v4, v3+v4, v2+v4 and v2+v6 vibrational modes were found to be excited in the radical; while in the CH2BrCl+hv→ Br (2P3/2)+CH2Cl channel, the excited vibrational modes were v2+v6, v1+v3, v2+v5, v2+v3+v5, and v1+v5. The results further implied that, following absorption of one photon by the parent molecule CH2BrCl, other vibrational modes besides v5 (CBr stretch) mode, such as v7 (CH2 a-stretch) mode, are excited in the parent molecule.

Key words: CH2BrCl, Photodissociation, Velocity map ion-imaging, Impulsive model invoking angular momentum conservation, Vibrational internal energy distribution