NCS自由基与NO反应动力学的理论研究

Theoretical Studies on Kinetics Reaction for the Reaction ofNCS Radical and NO

用量子化学密度泛函理论 B3 LYP/ 6-3 1 +G*和高级电子相关校正的偶合簇 [CCSD( T) / 6-3 1 1 +G*]方法 ,对 NCS自由基与 NO反应的机理和动力学进行了理论研究 ,得到了体系的势能面信息和可能的反应机理 .计算了反应的热力学参数及反应能垒 .采用传统过渡态理论计算了各反应通道的速率常数 .研究结果表明 ,NCS自由基与 NO反应中存在 4个反应通道 ,产物分别为 OCS+N2 ,CS+N2 O,ONS+CN和 ONCNS.从能量变化和反应速率两方面考虑 ,NCS +NO OCS+N2 应为主反应通道 .

DFT-B3LYP was used to calculate the geometries of reactants, intermediates, transition states and products for NCS + NO reaction on the 6-31+G * level. The transition states and intermediates of the reaction were verified by frequency analysis. The intrinsic reaction coordinate(IRC) calculations at the same level were also carried out to check the connection between all the critical structures located on the potential energy surface. Single point energies were calculated on the CCSD(T)/6-311+G * level. The energy barriers, rate constants and thermodynamic quantities of the reaction were also calculated. The results show that the reaction system of the title reaction involves four paths, producing OCS+N 2(1), CS+N 2O(2), NS+OCN(3) and ONCNS(4) products, respectively. The NCS+NOOCS+N 2 is the dominant reaction path.