Infrared spectroscopy and 266 nm photolysis of H2S2 in solid Ar

The infrared spectra of H2S2 and its 266 nm photolysis products are studied in an Ar matrix at 7.5 K. The antisymmetric and symmetric HS-stretching, and the antisymmetric bending of H2S2 are assigned at 2556.6, 2553.8 and 880.3 cm−1, respectively. The absorptions appearing during the photolysis at 2463, 2460 and 903 cm−1 are tentatively assigned to the HS2 radical. The two main dissociation channels are: H2S2+hν → HS2+H and H2S2+hν → S2+H2, with a branching ratio close to 1.