Effects of (H2S)2 Formation and Added H2O on Ultraviolet Photooxidation of Hydrogen Sulfide in an O2 Matrix

Article abstract of DOI:10.1021/j100280a120

UV photooxidation of H2S effected by λ = 270-300 nm in an O2 matrix at 13 K has been studied for a wide range of the matrix:solute ratios, 200-8000.The H2S:O2 = 1:8000 sample represents the limiting case of matrix-isolated H2S monomer and gives the product ratio of SO2:SO3:H2SO4 = 1:0.5:0.1, whereas the H2S:O2 = 1:200 sample represents the limiting case of (H2S)2 dimer and gives the product ratio of 1:0.1:0.02.The photochemical formation of the S(VI) products is substantially reduced by the (H2S)2 dimer formed during the preparation of the concentrated matrix sample, and the H2S partner in the dimer acts as a reducing agent of a photooxidation precursor.However, it appears that the H2O partner of the H2S*H2O complex formed in the H2S/H2O/O2 matrix samples neither enhances nor suppresses the H2S photooxidation process that gives the S(VI) products in an O2 matrix.