异硫氰酸与CF_2自由基反应机理的量子化学研究  

Theoretical study of the reaction mechanism for CF_2 Radical with isothiocyanic acid

作　　者：侯丽杰[1] 孔超[1] 韩彦霞[1] 陈东平[1] 高立国[2] 

机构地区：[1]陇东学院化学化工学院,庆阳745000 [2]榆林学院化学化工学院,榆林719000

出　　处：《原子与分子物理学报》2012年第6期988-996,共9页Journal of Atomic and Molecular Physics

基　　金：陇东学院青年科技创新基金(XYZK0717)

摘　　要：采用密度泛函理论B3LYP方法研究了CF_2自由基与HNCS的反应机理,并在B3LYP/6-311++G**水平上对反应物、中间体、过渡态进行了全几何参数优化,通过频率分析和IRC确定中间体和过渡态的真实性.为了得到更精确的能量值,又用CCSD(T)/6-311++G**方法计算了在B3LYP/6-311++G**水平优化后的各个驻点的相对能量.根据统计热力学及用Winger校正的Eyring过渡态理论,利用自编程序,计算不同温度下低势垒反应的平衡常数和速率常数.计算结果表明,单重态的CF_2自由基与HNCS的反应有6条可能的反应通道,三重态的CF_2自由基与HNCS的反应有1条反应通道.其中单重态反应通道CF_2+HNCS→IM1→TS1→IM2 HCF_2NCS(P1)为主反应通道.The reaction mechanism of CF2 radical with HNCS has been investigated by a B3LYP method of density functional theory, while the geometries and harmonic vibration frequencies of reactants, intermediates,transition states and products have been calculated at the B3LYP/6-311＋＋G＊＊ level. Intermediates and transition states were confirmed by the results of vibration analysis and the IRC calculation. To obtain more precise energy result, stationary point energies were calculated at a CCSD （T）/6- 311-P＋G＊＊//B3LYP/6-311＋＋G＊＊ level. In temperature range of 100 to 2300 K, the statistical thermodynamics and Eyring transition state theory with Winger correction are used to study the thermodynamic and kinetic characters of the channel with low energy barrier at 1.0 atm. The reaction CF2 ＋HNCS→IM1→TS1→IM2 HCF2NCS（P1） was the main pathway with larger equilibrium constant and higher rate constant, HCFzNCS was the main product.

关 键 词：CF2自由基 HNCS 反应机理 自然键轨道理论 电子密度拓扑分析 

分 类 号：O64[理学—物理化学]