Sun Shengmin, Zhang Kun, Lu Yang, Wang Aihua, Zhang Hui
College of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin, 150080, People's Republic of China.
J Mol Model. 2014 Jul;20(7):2288. doi: 10.1007/s00894-014-2288-3. Epub 2014 Jun 17.
A theoretical investigation on the multiple-channel degradation mechanism of carbaryl with ·OH in the atmosphere was completed by the variational transition state theory. Eleven reaction channels have been identified using the density functional theory. The equilibrium geometries and the corresponding harmonic vibrational frequencies of the stationary points were obtained at the B3LYP/6-31++G(d,p) level. The minimum energy paths were calculated at the same level, and energetic information was further refined at the B3LYP/6-31++G(3df,2p) level. The rate constants of the 11 reaction channels were calculated by improved canonical variational transition state theory with small-curvature tunneling correction over the temperature range 200-800 K. The total rate constants are in good agreement with available experimental data and the three-parameter expression k(T) = 1.85 × 10(-21) T (3.44)exp(1180.18/T) cm(3) molecule(-1) s(-1) was given.
通过变分过渡态理论完成了对西维因在大气中与·OH的多通道降解机理的理论研究。使用密度泛函理论确定了11个反应通道。在B3LYP/6-31++G(d,p)水平上获得了驻点的平衡几何结构和相应的谐振频率。在同一水平上计算了最小能量路径，并在B3LYP/6-31++G(3df,2p)水平上进一步完善了能量信息。通过改进的正则变分过渡态理论结合小曲率隧道效应校正，计算了200-800 K温度范围内11个反应通道的速率常数。总速率常数与现有实验数据吻合良好，并给出了三参数表达式k(T) = 1.85 × 10(-21) T (3.44)exp(1180.18/T) cm(3) molecule(-1) s(-1) 。
