Photochemistry and Non-adiabatic Photodynamics of the HOSO Radical

Hydroxysulfinyl radical (HOSO) is
important due to its involvement
in climate geoengineering upon SO2 injection and generation
of the highly hygroscopic H2SO4. Its photochemical
behavior in the upper atmosphere is, however, uncertain. Here we present
the ultraviolet–visible photochemistry and photodynamics of
this species by simulating the atmospheric conditions with high-level
quantum chemistry methods. Photocleavage to HO + SO arises as the
major solar-induced channel, with a minor contribution of H + SO2 photoproducts. The efficient generation of SO is relevant
due to its reactivity with O3 and the consequent depletion
of ozone in the stratosphere.