物理化学学报 >> 1999, Vol. 15 >> Issue (03): 247-252.doi: 10.3866/PKU.WHXB19990310

研究论文 上一篇    下一篇

HNCO+OH->H2O+NCO的反应机理

石土金, 李宗和, 刘若庄   

  1. 北京师范大学化学系,北京 100875
  • 收稿日期:1998-05-07 修回日期:1998-10-05 发布日期:1999-03-15
  • 通讯作者: 刘若庄

Mechanism of Reaction HNCO+OH->H2O+NCO

Shi  Tu-Jin, Li Zong-He, Liu Ruo-Zhuang   

  1. Department of Chemistry,Beijing Normal University,Beijing 100875
  • Received:1998-05-07 Revised:1998-10-05 Published:1999-03-15
  • Contact: Liu Ruo-Zhuang

摘要:

采用从头算分子轨道法 (UHF/6 31G**水平 ,并用MP4加以相关能校正 )研究了HNCO +OH→H2 O +NCO反应机理 .同时用Morokuma数值法获得了反应途径即内禀反应坐标 (IRC) .沿着IRC ,运用反应途径哈密顿理论 ,获得反应途径动态学信息 .在此基础上 ,根据过渡态理论和相应隧道效应校正 ,计算了在不同温度下的反应速率常数 ,得到了和实验相一致的结果 .计算结果表明 ,此反应是一步直接型的抽提H反应 .

关键词: 反应机理, 内禀反应坐标, 反应速率常数, 从头算分子轨道法

Abstract:

The mechanism of the reaction HNCO +OH→H2 O +NCO has been studied by using ab initio MO method(at UMP4/6 31G** level) with energy gradient technique. The reaction path was traced with Fukui’s theory of intrinsic reaction coordinate (IRC). Along the IRC, some dynamics properties were investigated by applying reaction path Hamiltonian theory. On this basis, the rate constants of the reaction at different temperatures were calculated by transition state theory with correction of quantum effect. The theoretically calculated rate constants are in good agreement with experimental results. This shows that the reaction is a direct reaction of hydrogen abstraction with only one step.

Key words: Reaction mechanism, Intrinsic reaction coordinate, Reaction rate constants, Ab initio MO method