HNCS与NO自由基反应机理的理论研究

Theoretical study of the reaction mechanism for HNCS with NO radical

用从头算法HF,在6-31G(d,p)机组水平上系统研究了HNCS与NO自由基反应的机理.全参数优化了各反应驻点物种的几何构型,并在相同水平上通过频率计算和内禀反应坐标(IRC)分析对过渡态结构及连接性进行了验证.用全电子QCISD(T)方法对各驻点进行了单点能量校正.通过反应位垒的比较找出了主反应通道,同时给出了其他的反应通道.结果表明,HNCS与NO自由基的反应有3条通道,通道a生成产物为HNNO和CS,通道b和通道c的生成产物均为HNN和SCO,通过反应位垒与反应热的比较,得出反应通道c为主要反应通道.

The reaction mechanisms of HNCS with NO radical have been systematically investigated using abinitio （HF method） at the HF/ 6-31＋G （d,p） level. The geometries of the transition states, the intermediates have been completely optimized. The transition states and intermediates of these reactions are verified by frequency analysis. The relation ship of reactants, transition states, intermediates and products is affirmed by IRC. The energies of all species have also been further calculated using QCISD （T）. The results show that the reaction HNCS＋NO involves three channels. By the energy barriers and thermodynamic quantities comparison, the third channel in which the HNN and SCO have been produced is the dominant one.