乙烯酮自由基(HCCO)与臭氧(O_3)反应势能剖面的理论研究

Theoretical Study on the Potential Energy Surface of the Reactions between HCCO and O_3

采用密度泛函B3LYP/6-311G**水平研究了基态乙烯酮自由基HCCO(2A″)与臭氧分子O3反应机理,全参数优化了反应势能面上各驻点的几何构型,并在此水平优化的几何构型基础上,使用CCSD(T)/6-311G**方法进行了单点能校正,另外,用内禀反应坐标(IRC)计算和频率分析方法,对过渡态进行了验证.结果表明:乙烯酮自由基HCCO(2A″)与臭氧之间有很强的反应活性,按不同的反应通道生成不同的产物P1-P8,而产物P1-P6的反应活化能稍低,则产率相对较高,且均为放热反应.

The reaction mechanism between ozone molecule and ketyl radical （HCCO： ^2A＂）has been studied by using the density functional theory （DFT） at B3L YP/6-311G^＊＊ level. The geometries for reactants, the transition states and the products are completely optimized. Based on B3L YP/6- 311G^＊＊ geometries, single point CCSD（T）/6-311G^＊＊ energy calculations have been performed to get more accurate energies. In addition, all the transition states are verified by the frequency analysis and the intrinsic reaction coordinate （IRC） calculations. The obtained results show that ketyl radical （HCCO： ^2A＂） trends intensively to react with the ozone. There are different reaction channels to the mechanism of the title reaction, producting P1-P8 product. The reaction barrier is lower and reaction activity is higher to product P1-P6. So it happens easily. The reaction is strongly exothermic.