Red and near-infrared laser-induced emission of S2 in an Ar matrix

Abstract

The S2 emission in the red and near-infrared regions has been reinvestigated using the laser-induced emission technique. Four progressions of S2 in solid Ar were observed in the emission spectra following excitation in the UV region with a pulsed Nd-YAG laser system. 34S-isotopic shifts allowed the determination of spectroscopic parameters for these progressions. Among them, ν00=19 757 and 15 417 cm−1 for the two progressions with distinct zero-phonon lines (ZPL); ν00=19 384 and 15 003 cm−1 for the other two with no ZPL, respectively. The progressions are assigned as the c 1Σ−u→X 3Σ−g and the c 1Σ−u →a 1Δg transitions of S2 in two matrix sites, respectively. The data yield the T0 values for the c 1Σ−u and the a 1Δg states. The relative intensities of these four progressions varied with excitation wavelengths and isotopic species.