高等学校化学学报

高等学校化学学报 ›› 1993, Vol. 14 ›› Issue (8): 1122.

• 研究论文 • 上一篇    下一篇

烷烃和胺类分子对电子激发态CH(A2Δ和B2Σ-)自由基猝灭

陈从香, 冉琴, 俞书勤, 马兴孝   

  1. 中国科技大学近代化学系, 合肥 230026
  • 收稿日期:1992-09-03 修回日期:1993-04-09 出版日期:1993-08-24 发布日期:1993-08-24
  • 通讯作者: 陈从香
  • 作者简介:第一作者:男, 52岁, 副教授.
  • 基金资助:

    国家自然科学基金

Quenching of CH(A,B) Radicals by Alkane and Amine Molecules

CHEN Cong-Xiang, RAN Qin, YU Shu-Qin, MA Xing-Xiao   

  1. Department of Modern Chemistry, University of Science and Technology of China, llefei, 230026
  • Received:1992-09-03 Revised:1993-04-09 Online:1993-08-24 Published:1993-08-24

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摘要： 用266nm激光光解CHBr3分子产生CH(A,B)态自由基,通过测量CH(A,B→X)自发辐射的时间分辨信号测定室温下(CH3)2NH、(C2H5)2NH、(C2H5)3N、n-C5H12、n-C6H14和n-C7H16对CH(A,B,v'=0)的猝灭速率常数.发现猝灭速率常数与猝灭剂烷烃分子中的C-H键数近似成线性关系,但对大的烷烃分子,这种增加逐渐趋缓.用碰撞络合物模型计算胺类分子及烷烃分子与CH形成碰撞络合物时的生成截面,结果表明,在电子激发态CH自由基的猝灭过程中,碰撞对子间的多极相互吸引势和色散力作用势可能起重要作用.

关键词: CH自由基, 胺类分子, 烷烃分子, 猝灭

Abstract: The measurements of quenching rate constants of CH(A,B) radicals by (CH3)2NH, (C2H5)2NH, (C2H5)3N, n-C5H12, n-C6H14 and n-C7H16 are presented by using laser photolysis of CHBr3 at 266 nm and time-resolved fluorescence quenching technique.It is found that the quenching rate constants for both Aand Bstates increase almost linearly with increasing C-Hnumber contained in the alkane molecule.But for larger alkane molecules, it appears that the quenching rate increase is smaller than that for small alkane molecules.The formation cross sections of complexes between electronically excited CHand amine and alkane molecules were calculated by using collision complex model.It is found that the dependence of the formation cross section of complex on the number of C-Hbonds in the alkane molecules is in good agreement with that of the measured quenching cross section.This implies that the attractive forces between CH (Aand B) and alkane molecules are probably important in collisional quenching processes of CH (Aand B) by alkane molecules.The similar conclusion could be drawn for quenching of CH(Aand B) by amine molecules.

Key words: CH radical, Amine molecule, Alkane molecule, Quenching

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