氧气和CS自由基反应势能面的密度泛函理论研究

Theoretical Study on Reaction Mechanism of the CS Radical with Oxygen

应用量子化学从头计算和密度泛函理论 (DFT)对O2 和CS自由基的反应进行了研究 .在B3LYP/6 3 11G 水平上计算出了各物种的优化构型、振动频率和零点振动能 (ZPVE) .各物种的总能量由CCSD(T) /6 3 11G //B3LYP/6 3 11G 给出 ,并对总能量进行了零点能校正 .计算结果表明 :CS自由基中的C端沿着O2 的双键中线方向进攻 ,进行加成反应 ,反应的第一步放出大量的热量 ( 4 5 1kJ/mol) ,推动反应继续进行 .从稳定的中间体 4(Cs)出发 ,反应主要通过O的相邻位置的迁移生成P1 (CO +SO)和P3 (COS +O) ;通过S的相邻位置的迁移生成了重要的反应复合物 (complex 1) ,进一步离解为产物P2(CO2 +S) .

The singlet potential energy surface for the CSO2 system was investigated at the hybrid density functional B3LYP and CCSD(T) (single-point) levels with 6-311G* * basis set in order to clarify the reaction mechanism of the radical CS with oxygen. It is shown that the C-site of the CS radical attacks the O-2 bond and forms the isomer 4. The entrance step gives out a lot of energy. The isomer 4 undergoes the 1, 2 O-atom shift or the 1, 2 S-atom shift and ultimately forms the products. This mechanism can excellently express the formation of the P-1( CO + SO), P-2(CO2 + S) and P-3(COS+O).