物理化学学报 >> 2002, Vol. 18 >> Issue (05): 446-450.doi: 10.3866/PKU.WHXB20020513

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CH2O＋O[3P]→CHO＋OH反应途径和变分速率常数

李会英;冯文林;冀永强;徐振峰;雷鸣   

  1. 北京化工大学应用化学系,北京　100029
  • 收稿日期:2001-10-09 修回日期:2001-12-05 发布日期:2002-05-15
  • 通讯作者: 冯文林 E-mail:wlfeng@buct.edu.cn

The Reaction Path and Variational Rate Constant of the Hydrogen Abstraction Reaction CH2O＋O[3P]→CHO＋OH

Li Hui-Ying;Feng Wen-Lin;Ji Yong-Qiang;Xu Zhen-Feng;Lei Ming   

  1. Department of Applied Chemistry,Beijing University of Chemical Technology,Beijing　100029
  • Received:2001-10-09 Revised:2001-12-05 Published:2002-05-15
  • Contact: Feng Wen-Lin E-mail:wlfeng@buct.edu.cn

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摘要： 采用QCISD/6311G[d,p]从头算方法,优化了吸氢反应CH2O＋O[3P]→CHO＋OH的反应物、过渡态和产物的几何结构,并用QCISD(t,full)/6311G//QCISD/6311G方法对各驻点进行了单点校正,得出正逆反应的活化位垒分别为38.86 kJ•mol－1和67.23 kJ•mol－1.IRC（内禀反应坐标）分析指出,该反应是一个C－H键断裂和H－O键生成协同进行的反应,而且在反应途径上存在一个引导反应进行的振动模式,其引导反应进行s区间为－0.4～0.75 (amu)1/2.在1 300～2 270 K温度范围内运用改进的变分过渡态理论（ICVT）,计算了反应速率常数,与实验结果相当一致.

关键词: 甲醛, 三线态氧, 速率常数, 从头算法, 变分过渡态理论

Abstract: Using ab initio molecular orbital theory,the hydrogen abstraction reaction CH2O＋O[3P]→CHO＋OH has been studied.The geometries of the reactants,transition state and products have been optimized at the QCISD/6311G[d,p] level.The forward and reverse reaction potential barriers are 38.86 kJ•mol－1 and 67.23 kJ•mol－1 respectively at the QCISD(t,full)/6311G[d,p]//QCISD/6311G[d,p].By analyzing the changes of the generalized normalmode vibrational frequencies along the IRC,we found that the C－H bond breaking and the O－H bond forming took place as a concerted process.And there is a reactive vibrational normalmode which leads to the process of reaction from reactants to products.At the temperature range of 1 300～2 270 K,the forward and reverse reaction rate constants obtained by using the improved canonical variational transition state theory (ICVT),are consistent with the experimental values.

Key words: Formaldehyde, O[3P], Rate constant, Ab initio