物理化学学报 >> 2006, Vol. 22 >> Issue (01): 6-10.doi: 10.3866/PKU.WHXB20060102

研究论文 上一篇    下一篇

乙烯自由基A2A''(v'=0)←X2A'(v''=0)带的转动分析

周晓国; 刘世林   

  1. 中国科技大学化学物理系, 合肥微尺度物质科学国家实验室(筹), 合肥 230026
  • 收稿日期:2005-05-26 修回日期:2005-06-20 发布日期:2006-01-15
  • 通讯作者: 周晓国 E-mail:xzhou@ustc.edu.cn

Rotational Analysis of the A2A''(v'=0)←X2A'(v''=0) Band of the Vinyl Radical

ZHOU Xiao-guo; LIU Shi-lin   

  1. Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, P. R. China
  • Received:2005-05-26 Revised:2005-06-20 Published:2006-01-15
  • Contact: ZHOU Xiao-guo E-mail:xzhou@ustc.edu.cn

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摘要： 通过193 nm光解丁烯酮分子产生乙烯基自由基(C2H3). 经射流冷却后, 用另一束激光光解C2H3, 生成的氢原子碎片经共振增强多光子电离(REMPI)过程, 记录氢离子信号随光解波长变化, 得到20020～20070 cm-1范围内乙烯基激发的转动分辨光谱. 该谱对应于A2A''(v'=0)←X2A'(v''=0)跃迁的转动结构. 结合量子化学理论计算、光谱拟合以及前人的研究结果, 对该段光谱进行了完整的转动识别, 确定了40条转动谱线的位置. 由光谱拟合还得到A2A''(v'= 0 )能级的预解离寿命为3.3 ps, 且不依赖于转动量子数.

关键词: 乙烯基, 共振增强多光子电离, 转动光谱, 预解离

Abstract: The vinyl radical was generated by photolysing methyl vinyl ketone with 193 nm laser, then was excited and photodissociated by another laser in the 20020～20070 cm-1 range. The dissociated H atom fragments were ionized and detected by (1+1′) resonance-enhanced multiphoton ionization (REMPI) process. The rotationally resolved action spectra of theA2A''(v'=0)←X2A'(v''=0)band of the vinyl radical were recorded by monitoring the H+ ion intensity with dissociation laser wavelength. The corresponding assignments were obtained with the aid of ab initio calculations and spectroscopic simulations, and 40 rotational lines were definitely assigned. Additionally, the predissociative lifetime of the •C2H3 A2A''(v'= 0 ) state was 3.3 ps and independent of the rotational levels, which was derived from the linewidth.

Key words: Vinyl radical, Resonance-enhanced multiphoton ionization, Rotational spectroscopy, Predissociation