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研究论文

碘代烷烃在532nm激光作用下多光子电离解离机理

章莲蒂;魏杰;方黎;姜芸芸;张树东;郭文跃;张柏林;张冰;蔡继业   

  1. 中国科学院安徽光学精密机械研究所激光光谱开放实验室
  • 发布日期:1999-01-15

Multiphoton ionization mass spectra of alkyl iodies at 532nm

Zhang Liandi;Wei Jie;Fang Li;Jiang Yunyun;Zhang Shudong;Guo Wenyue;Zhang Bailin;Zhang Bing;Cai Jiye   

  • Published:1999-01-15

利用532nm的激光对碘代烷烃(碘甲烷,碘乙烷,碘代正丙烷,碘代异丙烷)分子作了多光子电离解离(MPID)质谱(MS)研究。在532nm激光作用下,CH3I分子吸收532nm激光双光子的能量,进入A带的1A2态,继续吸收光子上泵浦至电离态形成母体离子CH3I^+,然后再形成碎片离子;而其它几个碘代烷烃吸收双光子的能量进入A带后均形成中性碎片,中性碎片再吸收光子经一系列电离解离形成碎片离子。此外,本文还通过对同分异构分子n-C3H7I与i-C3H7I分支比的分析给出i-C3H7I分子的可能的电离解离通道。

关键词: 碘代烃, 激光应用, 激光器, 多光子过程, 电离

Multiphoton Ionization-Dissociation (MPID) Mass Spectra (MS) of alkyl iodides (including methyl iodide, ethyl iodide, n-propyl iodide and i-propyl iodide) are obtained using a time-of-flight mass spectrometer at 532nm. It is found that all kinds of parent molecules are first two-photon resonantly excited to A-band. CH3I molecule is resonantly exited to 1A2 state of A-band, and its MPID belongs to parent-ion ladder mechanism. However other moleculles are resonantly exited to A-band and then go through dissociation. Fragment ions are produced by ionization and dissociation of neutral fragments. Their MPID belongs to neutral-fragment photoionization mechanism. Moreover, the dissociation pathways of isopropyl cation are discussed through branching ratio analyses.

Key words: IODOHYDROCARBON, LASER APPLICATION, LASER, MULTIPHOTON PROCESSES, IONIZATION

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