H_2O(HOD)+Cl→HCl(DCl)+OH(OD)反应动态学的理论研究

Theoretical Studies on Reaction Dynamics of H_2O(HOD) +Cl→HCl(DC1) +OH(OD)

用从头算方法,获得了H_2O+Cl→HCl+OH(R1),HOD+Cl→DCl+OH(R2)及HOD+Cl→HCl+OD(R3)反应的内禀反应坐标(IRC).根据传统过渡态、变分过渡态理论及相应的隧道效应校正,计算了反应的速率常数.对已有实验速率常数值的R1反应,我们计算的结果和实验一致.根据Truhlar的振动选态公式,分别讨论了激发HOD中OH,OD振动模式对反应速率的影响,得到激发HOD中的OH振动模式将有利于产物OD十HCl生成,和实验的结论相一致.

Based on ab initio methods with gradient technique, the intrinsic reaction coordinate (IRC) of the reactions H2O +Cl→HCl + OH (R1), HOD + Cl→DCl + OH (R2) and HOD+Cl→HCl + OD (R3) are traced by using numerical method. The theoretical rate constants for the Rl ~R3 reactions are calculated by the conventional transition - state theory,variational transition -state theory and semiclassical vibrationally adiabatic transmission coefficients. The calculated rate constants for the Rl reaction are in good agreement with the experimental results. The state -selected reaction rate constants for the R2, R3 reactions are also calculated. It is concluded that the excitation of reactant HOD( nOH = 1) is beneficial to the production of product HCl + OD. This result agrees with experiment.