CH3自由基和O（^3P）反应机理的量子化学研究

Ab initio Study on the Reaction Mechanism of CH3 Radical and O(3P) Atom

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CH3 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水平上计算了能量 ,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 :CH3 自由基与O(3 P)反应有四条不同的放热反应通道 ,主反应通道为IM1→TS1→CH2 O +H ,同时反应可彻底裂解生成CO ,H2

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.