HOSO+X(X=F,Cl,Br)的反应机理及电子密度拓扑分析

在CCSD(T)/6-311++G(d, p)//MP2/6-311++G(d, p)水平上研究了HOSO+X(X= F, Cl,Br)的反应机理. 优化得到了反应势能曲线上各驻点的几何构型, 通过内禀反应坐标(IRC)确认了反应物、中间体、过渡态和产物的相关性. 在CCSD(T)/6-311++G(d, p)水平上对计算得到的构型进行了能量校正. 应用经典过渡态理论(TST)与变分过渡态理论(CVT), 并结合小曲率隧道效应模型(SCT)校正的方法, 计算了该反应在200~3000 K 温度范围内的速率常数k_TST,k_CVT 和k_CVT/SCT. 计算结果表明: HOSO+X(X= F, Cl, Br)反应在单态和三态条件下均可发生, 其中单态为主反应通道, HX+SO₂ 为主产物. 并利用电子密度拓扑分析方法研究了主反应通道化学键的变化.

Mechanism and topological analysis of the electron density of HOSO+X(X=F, Cl, Br) reactions

The reaction mechanisms of the reactions between HOSO and X(X=F, Cl, and Br) were investigated at the CCSD(T)/6-311++G(d, p)//MP2/6-311++G (d, p) level. The geometries of the reactants, transition states and the products were optimized at the MP2/ 6-311++G (d, p) level. The intrinsic reaction coordinates were traced according to Fukui's theory and the relationships between the transition states, the reactants and the products confirmed. The single point energies of the species were corrected at the CCSD(T)/ 6-311++G(d, p) level. Reaction rate constants were calculated over a temperature range of 200-3000 K using classical transition state theory and canonical variational transition state theory combined with a small-curvature tunneling correction. The results show that the HOSO+X(X= F, Cl and Br) reaction could occur in the singlet and the triplet reaction channels. The singlet reaction channels are dominant and HX + SO₂ are the main products. The formation and breaking of the chemical bond in the main reaction channel was analyzed by topological analysis of the electron density.