Atmospheric reaction between the HS radical and chlorine

The mechanism and the kinetics of the reaction between HS and Cl2 leading to HSCl and Cl were studied theoretically. The effect of the complete basis set limit (CBS) was included by extrapolating the results obtained with cc-pVDZ, cc-pVTZ and cc-pVQZ correlation consistent basis sets functions. At the highest level of calculation, CCSD(T), the calculated rate constant is 1.0×10−12 cm3 molecule−1 s−1. The activation Gibbs free energy was calculated to be 7.4 kcal/mol, which is only 0.2 kcal/mol above the value determined experimentally. The enthalpy and Gibbs free energies of the reaction are −6.9 and −6.5 kcal/mol, respectively.