物理化学学报 >> 2012, Vol. 28 >> Issue (05): 1045-1053.doi: 10.3866/PKU.WHXB201203061

热力学,动力学和结构化学 上一篇    下一篇

CH2BrCl在265 nm光解产生的氯甲基自由基的振动内能

张秀1, 吴东2, 唐碧峰1   

  1. 1. 湖北工程学院物理系, 湖北孝感 432000;
    2. 华中师范大学物理科学与技术学院, 武汉 430079
  • 收稿日期:2011-12-21 修回日期:2012-03-05 发布日期:2012-04-26
  • 通讯作者: 唐碧峰 E-mail:tangbf@wipm.ac.cn
  • 基金资助:

    湖北省教育厅科学技术研究项目(Z20082601)

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 E-mail:tangbf@wipm.ac.cn
  • Supported by:

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

摘要: 利用离子速度影像技术研究了CH2BrCl 在265 nm附近的激光光解. 利用2+1 共振增强多光子电离分别获得光解产物Br (2P1/2)和Br (2P3/2)的离子速度图像, 从而得出Br (2P1/2)和Br (2P3/2)的速度分布, 以及光解碎片的总平动能分布. 据此, 运用角动量守恒碰撞模型获得了解离氯甲基自由基(·CH2Cl)的振动内能分布. 研究结果表明: CH2BrCl+hv→Br (2P1/2)+CH2Cl 通道产生的氯甲基自由基中被激发的振动模主要是v4v3+v4v2+v4v2+v6; CH2BrCl+hv→Br (2P3/2)+CH2Cl 通道产生的氯甲基自由基中被激发的振动模主要是v2+v6v1+v3v2+v5v2+v3+v5v1+v5; 母体分子CH2BrCl 在吸收光解光子后除有v5 (CBr stretch)振动模被激发外, 还有v7 (CH2a-stretch)等其它振动模也被激发.

关键词: CH2BrCl, 光解, 离子速度影像, 角动量守恒碰撞模型, 振动内能分布

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

MSC2000: 

  • O643