HS和HONO反应机理的研究

Studies on the mechanism of the reaction between HS and HONO

采用密度泛函和耦合簇理论方法研究了HS与HONO的反应机理.在B3LYP/6-311+G(2df,2p)水平上对HS+HONO反应中的所有物种进行了几何构型优化和频率分析,通过内禀反应坐标(IRC)确认了反应物、过渡态、中间体和产物之间的相关性;采用CCSD(T)/6-311+G(2df,2p)方法获得了各物种的单点能.计算结果表明:HS+HONO的主要反应通道为HS+cis-HONO→p2-cis-IM1→p2-cis-TS→p2-IM2→P2(H_2S+NO_2),其反应活化能为71.26kJ·mol^(-1).

The mechanism of reaction between HS and HONO was investigated by means of DFT and CCSD（T）. The geometrical parameters of the reactants, transition states,intermediates and products were optimized at the 6-311＋G（2df,2p） computational levels. Based on the optimized geometries, the reactants ,transition states, intermediates and products were detected by frequency analysis. The intrinsic reaction coordinates（IRC） were traced and connecting relationships between the reactants,in- termediates, transition states and products were confirmed. The reliable single point energies of the species were computed by employing the CCSD（T） method. The result shows that the dominant reaction channel is HS＋ cis-HONO→p2-cis-IM1→p2-cis-TS→p2-IM2→P2 （H2 S＋ NO2 ）, and the apparent activation energy of the dominant reaction chananel is 71.26 kJ · mol-1.