高等学校化学学报

高等学校化学学报 ›› 1996, Vol. 17 ›› Issue (3): 456.

• 论文 • 上一篇    下一篇

电子激发态CH(C2Σ+)自由基的猝灭速率常数的测定

冉琴, 陈从香, 张群, 俞书勤, 李月寒, 马兴孝   

  1. 中国科学技术大学化学物理系, 合肥 230026
  • 收稿日期:1995-05-05 出版日期:1996-03-24 发布日期:1996-03-24
  • 通讯作者: 马兴孝
  • 作者简介:冉琴,女,27岁,博士.
  • 基金资助:

    国家自然科学基金

The Measurements of Quenching Rate Constants of Electronically Excited State CH (C2Σ+) Radical

RAN Qin, CHEN Cong-Xiang, ZHANG Qun, YU Shu-Qin, LI Yue-Han, MA Xing-Xiao   

  1. Department of Chemical Physics, University of Science and Technology of China, Hefei 230026
  • Received:1995-05-05 Online:1996-03-24 Published:1996-03-24

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摘要： 用266nm激光光解CHBr3分子产生CH(C)态自由基,通过测量CH(C2Σ+→X2Ⅱ)的总荧光信号强度来测定室温下O2、N2、n-C5H12、n-C6H14和n-C7H16对CH(C2Σ+,v'=0)的猝灭常数。结果表明,这些碰撞伴侣(O2和N2例外)对CH(X、A、B和C)的反应或猝灭速率常数k存在下列关系:k(X)>k(B)>k(A)≈k(C),且烷烃分子对CH(C)态的猝灭速率常数与对CH(X,A,B)态的反应和猝灭速率常数具有类似的规律,即随烷烃分子中的C-H键数的增加而增大。电子激发态CH的猝灭机制可能属于入口通道控制,化学反应在猝灭过程中起着重要作用。

关键词: CH自由基, 烷烃分子, O2, N2, 猝灭

Abstract: The rate constants for quenching of CH (C2Σ+,v'=0) by O2,N2,n-C5H12,n-C6H14 and n-C7H16 molecules were measured at room temperature.CH (C2Σ+) was produced by 266 nm laser photolysis of CHBr3 and the total fluorescence intensity of CH(C→X) at (314.8±1) nm was then monitored using a fast digital storage oscilloscope coupled with a microcomputer.The rate constants (k) for the total removal of CH (C)are compared with those of CH (X,A,B) states,and show to be k (X)>k(B) and k(C)for alkane quenchers,and the tendency of quenching rate constants for CH(C) is similar to those for CH(X,A,B)showing the increase with increasing the number of C-Hbonds in alkane molecules.The results indicate that the quenching of CH (A,B,C)is probably the entrance-channel controlled process and the chemical reaction might play an important role in collisional quenching of CH (A,B,C).

Key words: CH radical, Alkane molecule, O2, N2, Quenching

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