Conversion of SO2 to SO3 Facilitated by in Situ UV Photolysis of H2CO and SO2 in an O2 Matrix at 12 K

Article abstract of DOI:10.1021/j100282a013

The photooxidation product distributions observed in photolyses of H2CO and H2CO*SO2 molecular complexes in O2 matrices at λ = 270-420 nm are compared.Photodissociation of H2CO produces RO2 species, i.e., HO2 and HC(O)OO radicals, which then efficiently oxidize SO2 to SO3 (and H2SO4).This process occurs with an efficiency of ca. 0.7 +/- 0.3 per H2CO*SO2 molecular complex photodissociated.Various photooxidation mechanisms are considered.Implications of the low-temperature/matrix photooxidation results on atmospheric photooxidation of SO2 by RO2 species are discussed.