HO2与Cl反应机理及动力学性质的理论研究

Reaction mechanisms and kinetics for the reaction of HO2+Cl

揭示Cl对HO 2的消耗机制对改善大气环境质量具有指导作用,文中采用CCSD(T)/aug-cc-pVTZ//M06-2X/6-311++G(2d,2p)计算方法研究了HO 2+Cl抽氢和抽氧反应机理.研究发现,该反应共有R1(3O 2+HCl,路径1)、R2(1O 2+HCl,路径2)和R3(ClO+OH,路径3和路径4)三条反应通道,其中路径1和路径3分别为抽氢和抽氧通道的优势路径.利用经典过渡态理论(TST)与变分过渡态理论(CVT)并结合小曲率隧道效应模型(SCT),分别计算了抽氢和抽氧通道主路径1与路径3在213~320 K温度范围的内k CVT/SCT值.结果表明,在213~320 K温度范围内路径1的速率常数为4.69×10^-11~3.98×10^-10 cm^3·molecule^-1·s^-1,比路径3的速率常数高出了13~19个数量级,即路径1是HO 2+Cl反应进行的主通道,298 K时路径1的速率常数(6.27×10^-11 cm^3·molecule^-1·s^-1)与实验值(6.80×10^-11 cm^3·molecule^-1·s^-1)相吻合.此外,在213~320 K温度范围内,变分效应对路径1的速率常数影响较小,而隧道效应在低温段对路径1的速率常数有显著影响.

ion channels are calculated in the temperature range of 213-320 K.The rate constant of path 1 in the temperature range is 4.69×10^-11~3.98×10^-10 cm^3·molecule^-1·s^-1,which is larger 13-19 orders of magnitude than that of the path 3,It is shown that the path 1 are the favorable channel for the HO 2+Cl reaction.At 298 K,the rate constant of path 1 is 6.27×10^-11 cm^3·molecule^-1·s^-1,which is good agree the experimental value(4.10×10-11 cm^3·molecule^-1·s^-1).In addition,in the temperature range of 213~320 K,the recrossing effect has little effect on the rate constant of the path 1,while the tunneling effect has a significant effect on the rate constant of the path(1)in the low temperature range.