Kinetics of the gas-phase reaction of OH with HCl

The reaction of hydroxyl radicals with hydrogen chloride (reaction 1) has been studied experimentally using a pulsed-laser photolysis/pulsed-laser-induced fluorescence technique over a wide range of temperatures, 298-1015 K, and at pressures between 5.33 and 26.48 kPa. The bimolecular rate coefficient data set obtained for reaction 1 demonstrates no dependence on pressure and exhibits positive temperature dependence that can be represented with modified three-parameter Arrhenius expression within the experimental temperature range: k(1) = 3.20 x 10(-15)T(0.99) exp(-62 K/T) cm(3) molecule(-1) s(-1). The potential-energy surface has been studied using quantum chemical methods, and a transition-state theory model has been developed for the reaction I on the basis of calculations and experimental data. The model results in modified three-parameter Arrhenius expressions: k(1) = 8.81 X 10(-16)T(1.16) exp(58 K/T) cm(3) molecule(-1) s(-1) for the temperature range 200-1015 K and k(1) = 6.84 x 10(-19)T(2.12) exp(646 K/T) cm3 molecule(-1 s-1) for the temperature dependence of the reaction 1 rate coefficient extrapolation to high temperatures (500-3000 K). A temperature dependence of the rate coefficient of the Cl + H2O -> HCl + OH reaction has been derived on the basis of the experimental data, modeling, and thermochemical information.