Photodissociation of H2S doped in low temperature rare gas solids under UV irradiation Original Research Article

Hydrogen sulfide (H2S) doped in rare gas free standing crystals was photodissociated in ultraviolet (UV) region with changing the photolysis laser wavelength. The consumption of H2S and appearance of products were pursued by UV and IR absorption measurements. The threshold for the appearance of SH radicals was found to be located between 242 and 248 nm in Kr crystals, which corresponds to the minimum energy of 1.07–1.18 eV for the hydrogen (H) atoms to escape from the initial cage. This value is smaller than the threshold predicted by a sudden exit model, which implies the importance of delayed exit after energy transfer and distortion of the cage. No apparent difference in the threshold energy was noticed between the H atoms produced from the monomer H2S and those from the dimer (H2S)2 in the crystal.