摘要
用量子化学从头算和密度泛函理论 (DFT)对F原子与自由基CH2 SH在势能面上的反应进行了研究 .在B3LYP/ 6 311G 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B3LYP/ 6 311+G(2df,pd) / /B3LYP/ 6 311G 计算 ,另外对反应物和产物还计算了其G3能量 .结果表明 :首先F通过与C或S结合的两种途径与CH2 SH相配位 ,再通过H(4)原子转移形成甲基 ,然后甲基再旋转 ,甲基中H(4)原子最终与F结合 ,反应产物为HF和CH2 S .反应为放热反应 ,分别为ΔHr=- 370 .7kJ/mol(DFT)和 - 396 .94kJ/mol(G3) .此外依据计算出的反应热 ,可得自由基·CH2 SH的生成热ΔfHo2 98.15=14 6 .4 4kJ/mol (DFT) ,而ΔfHo0 =16 7.36kJ/mol (G3) .
The reaction of F atoms with . CH2SH radical has been studied by using quantum chemistry ab initio and density function theory (DFT) calculations along the potential energy surface. The optimized geometrical parameters, vibrational frequencies and zero-point vibrational energies (ZPVE) of all species were obtained at the B3LYP/6-311G* * theoretical level. The total energies were worked out using the B3LYP/6-311 + G(2df, pd)//B3LYP/6-311G* * method. In addition, the G3 energies of reactants and products were also obtained. The results indicate that the reaction proceeds through addition of a F atom to CH2SH by either F-C or F-S combination to form initial complexes, followed by H(4) migration to form methyl radical CH3 ., which rotates around main C-S bond to result in combination of H(4) and F. Formation of HF and CH2S is the most probable reaction channel with the exothermic heats of 396.94 kJ/mol (G3) and 370.7 kJ/mol (DFT) respectively. Furthermore, the enthalpy of formation of CH2SH was deduced to be 146.44 kJ/mol (DFT) and 167.36 kJ/mol (G3), which are in agreement with existing experimental and theoretical values.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2002年第10期1760-1767,共8页
Acta Chimica Sinica
基金
中国科学院知识创新基金资助项目
