用变分过渡态理论对CH3 SiH3 与氧原子O的抽提反应进行了理论研究。利用从头算计算了反应体系的构型、振动频率和能量等信息 ,分析了此反应的反应机理 ;在 2 9810 0 0K计算了主要反应通道的速率常数。结果表明 ,在低温下 ,变分对于此反应影响较大 ,隧道效应较明显 ;计算得到的室温速率常数和实验符合很好 Theoretical studies on the extraction of CH3 SiH3 and oxygen atom O using the theory of variational transition states have been carried out. The reaction mechanism was analyzed by ab initio calculation of the configuration, vibration frequency and energy of the reaction system. The rate constant of the main reaction channel was calculated at 28000K. The results show that at low temperature, the variation has a great effect on this reaction, and the tunnel effect is obvious. The calculated room temperature rate constant is in good agreement with the experiment