Laser-induced fluorescence studies of S2+ in solid argon

The laser-induced fluorescence of S2+ is studied in solid argon at 7.5 K. The S2+ molecular ions were generated under 266 nm photolysis of a H2S2/Ar matrix. The A 2Πu–X 2Πg emission of S2+ with a lifetime of 805 ns was detected while the matrix was excited in the 330–455 nm region. The assignment is based on the comparison of the measured spectroscopic parameters with the gas-phase values. The possible charge-transfer mechanism of the photogeneration of S2+ is discussed. Our results indicate that S2+ molecular ions constitute a minor channel in 266 nm photolysis of H2S2 in an Ar matrix.