【摘要】 采用QCISD/6-311G犤d,p犦从头算方法,优化了吸氢反应CH2O+O犤3P犦→CHO+OH的反应物、过渡态和产物的几何结构,并用QCISD(t,full)/6-311G//QCISD/6-311G方法对各驻点进行了单点校正,得出正逆反应的活化位垒分别为38.86kJ·mol-1和67.23kJ·mol-1.IRC(内禀反应坐标)分析指出,该反应是一个C-H键断裂和H-O键生成协同进行的反应,而且在反应途径上存在一个引导反应进行的振动模式,其引导反应进行s区间为-0.4～0.75(amu)1/2.在1300～2270K温度范围内运用改进的变分过渡态理论(ICVT),计算了反应速率常数,与实验结果相当一致.更多还原

【Abstract】 Using ab initio molecular orbital theory,the hydrogenion reaction CH2O+O→CHO+OH has been studied.The geometries of the reactants,transition state and products have been optimized at the QCISD/6 311G level.The forward and reverse reaction potential barriers are 38.86 kJ·mol-1 and 67.23 kJ·mol-1 respectively at the QCISD(t,full)/6 311G//QCISD/6 311G.By analyzing the changes of the generalized normal mode vibrational frequencies along the IRC,we found that the C-H bond breaking and the O-H bond forming took place as a concerted process.And there is a reactive vibrational normal mode which leads to the process of reaction from reactants to products.At the temperature range of 1 300～2 270 K,the forward and reverse reaction rate constants obtained by using the improved canonical variational transition state theory (ICVT),are consistent with the experimental values.更多还原