H+HNCO→NH_2+CO的反应机理及动态学计算

Calculations on the Mechanism and Dynamics of the Reaction H + HNCO→NH_2 + CO

用从头算方法研究了H+HNCO→NH_2+CO的反应机理:首先经过H_2NCO中间体,并为反应的控制步骤.在此基础上,计算了控制步骤的反应途径,沿反应途径的动态学性质和正则变分过渡态理论的速率常数.结果表明,反应存在返回效应和隧道效应,反应途径的曲率对隧道效应影响较大,用变分过渡态方法和小曲率近似方法分别进行校正是有效的.

The mechanism of the reaction H + HNCO→NH2 + CO that the first step producing an intermediate H2NCO complex is a controlling step has been calculated by ab initio MO method. On this basis, the reaction path, the dynamical properties along the reaction path and CVT (canonical variational theory) rate constants of the controlling step were investigated. The results show that the recrossing and tunneling effects exist and the corrections by means of CVT method and small curvature approximation method are efficient respectively.