SiH3＋O（^3P）反应机理的理论研究

Theoretical Study on the Reaction Mechanism of SiH3+O(3P)

利用abinitio方法对SiH3+O(3P)反应进行了理论研究,在MP2/6-311+G(d,p)水平上优化得到了反应途径上的反应物、中间体、过渡态和产物的几何构型,并在QCISD(T)/6-311+G(d,p)水平上进行单点能计算.计算结果表明,SiH3+O(3P)→IM1→TS3→IM2→TS8→HOSi+H2为主反应通道,其他可能存在的次要产物有HSiOH+H、H2SiO+H和HSiO+H2.HOSi、HSiO和HSiOH(cis)还可能进一步解离生成SiO.另外,计算结果对SiH4+O(3P)反应机理中存在的争议给出了可能的解释,认为Withnall等人在实验中观察到的产物HSiOH、H2SiO和SiO并不是SiH4+O(3P)反应的直接产物,而是来自副反应SiH3+O(3P).

The reaction for SiH3 ＋ O（^3p） was studied by ab initio method. The geometries of the reactants, intermediates, transition states and products were optimized at MP2/6-311 ＋ G（d, p） level. The single-point calculations for all the stationary points were carried out at the QCISD（T） /6-311 ＋ G（d,p） level using the MP2/ 6-311 ＋G（d,p） optimized geometries. The results of the theoretical study indicate that the major pathway is the SiH3 ＋ O（^3p）→IM1→TS3→IM2→TS8→HOSi ＋ H2. The other minor products include the HSiOH ＋ H, H2SiO ＋ H and HSiO ＋ H2. Furthermore, the products HOSi, HSiO and HSiOH （cis） can undergo dissociation into the product SiO. In addition, the calculations provide a possible interpretation for disagreement about the mechanism of the reaction SiH4 ＋ O （^3p）. It suggests that the products HSiOH, H2SiO and SiO observed by Withnall and Andrews are produced from the secondary reaction SiH3 ＋ O（^3p） and not from the reaction SiH4 ＋ O（^3p）.