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化学学报
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化学学报 ›› 2002, Vol. 60 ›› Issue (7): 1186-1191. 上一篇    下一篇

研究论文

CH_3自由基和O（~3P）反应机理的量子化学研究

李来才;邓萍;李德华;田安民   

  1. 四川师范大学化学系,成都(610066);四川大学化学系,成都(610064)
  • 发布日期:2002-07-15

Ab initio Study on the Reaction Mechanism of CH_3 Radical and O(~3P) Atom

Li Laicai;Deng Ping;Li Dehua;Tian Anmin   

  1. Department of Chemistry, Sichuan Normal University, Chengdu(610066);Department of Chemistry, Sichuan University,Chengdu(610064)
  • Published:2002-07-15

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用分子轨道从头计算MP2（full）方法和密度泛函理论（DFT）中的B3LYP方法 研究了CH_3自由基和三线态O原子反应的微观机理，优化得到了反应途径上的反应 物、过渡态、中间体和产物的几何构型，通过振动分析对过渡态和中间体构型进行 了确认，在G3不平上计算了能量，同时用经典过渡态理论对该反应的绝对速率常数 进行了理论计算。研究结果表明：CH_3自由基与O（~3P）反应有四条不同的放热反 应通道，主反应通道为IM1→TS1→CH_2O + H，同时反应可彻底裂解生成CO, H_2 及H。

关键词: 甲烷, 游离基, 过渡态, 分子轨道, 从头计算法, 构型

The reaction of CH_3 radicals with O(~3P) atoms was studied theoretically by means of the Gaussian-3 (G3) model calculation. The structures of the stationary points were optimized at the MP2 (full)/6- 31G~* and B3LYP/6-311 + + G~(**) level, and the intermediates and transition states were detected by the frequency analysis. At the same time, the energies yielded using the G3 model, and dynamics of the reaction were also discussed in this paper. The results of the theoretical study indicate that the CH_3 + O (~3P) reaction has four possible exothermic channels in which the main channel is IM1 → TS1 → CH_2O + H and the reaction forms CO by complete decomposition.

Key words: METHANE, FREE RADICAL, TRANSITION STATE, MOLECULAR ORBIT, AB INITIO CALCULATION, CONFIGURATION

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