Ab initio study of the potential energy surface and product branching ratios for the reaction of O(1D) with CH3CH2F

The potential energy surface of O(1D) + CH3CH2F reaction has been studied using QCISD(T)/6-311++G(d,p)//MP2/6-311G(d,p) method. The calculations reveal an insertion-elimination reaction mechanism of the title reaction. The insertion process has two possibilities: one is the O(1D) atom inserting into C-F bond of CH3CH2F produces one energy-rich intermediate CH3CH2OF and another is the O(1D) atom inserting into one of the C-H bonds of CH3CH2F produces two energy-rich intermediates, IM1 and IM2. The three intermediates subsequently decompose to various products. The calculations of the branching ratios of various products formed though the three intermediates have been carried out using RRKM theory at the collision energies of 0, 5, 10, 15, 20, 25 and 30 kcal/mol. CH3CH2O is the main decomposition product of CH3CH2OF. HF and CH3 are the main decomposition products for IM1; CH2OH is the main decomposition product for IM2. Since IM1 is more stable and more likely to form than CH3CH2OF and IM2, HF and CH3 are probably the main products of the O(1D) + CH3CH2F reaction. Our computational results can give insight to reaction mechanism and provide probable explanations for future experiments.