Oxidation of HOSO by Cl: a new source of SO2 in the atmosphere?

In the present work, we have studied the formation of SO2 in the atmosphere from the oxidation of HOSO by Cl at the CCSD(T)/aug-cc-pV(+d)TZ//MP2/aug-cc-pV(+d)TZ level of theory. The present work reveals that the title reaction is a barrierless reaction that proceeds through a stable intermediate sulfurochloridous acid having a stabilization energy of similar to-56.5 kcal mol(-1). The rate constant values within the temperature range of 213-400 K indicate that the rate of HOSO + Cl = SO2 + HCl reaction does not change much with the change in temperature. Besides, the reaction was also found to be insensitive towards pressure change. Interestingly, the relative rate of HOSO + Cl reaction with respect to HOSO + OH reaction indicates that HOSO + Cl is always much slower than HOSO + OH reaction, within the temperature range of 213-400 K.