Oxidation of HOSO[rad] by NH2[rad]: A new path for the formation of an acid rain precursor

Abstract

In the present investigation, we have studied the possibility of the formation of SO2 from the oxidation of HOSO by NH2 employing CCSD(T)/ aug-cc-pVQZ//MP2/aug-cc-pV(+d)TZ level of theory. The results indicate that the formation of SO2 from HOSO + NH2 reaction is a barrierless process with an effective barrier of ~−37.72 kcal mol−1, which proceeds through a stable intermediate sulfuramidous acid (H3NO2S). The calculated rate constants for HOSO + NH2 reaction shows an anti Arrhenius behavior within the temperature range of 213–400 K and at 298 K, it was found to be ~1.39 × 10−11 cm3 molecule−1 sec−1. We have also studied the pressure dependency of HOSO + NH2 reaction, which suggests that the rate constant values are not sensitive towards the pressure change.