Laser spectroscopy of the A˜2A′ − X˜2A′′ system for the HSO radical

Rotationally resolved spectra of the A˜2A′-X˜2A″ system for the HSO radical were observed by laser induced fluorescence spectroscopy. The radical was produced in a discharged supersonic jet of a gas mixture of dimethyl disulfide and O2 diluted in Ar. The observed spectra were assigned to ro-vibronic transitions of the Ka′←Ka″ = 0 ← 1, 1 ← 0, and 2 ← 1 subbands of A˜(00v3′)-X˜ (0 0 0) with v3′ = 0-8, and those of A˜ (0 1 3) − X˜ (0 0 1), yielding the rotational and spin-rotation interaction constants for the excited electronic state. For the vibronic origin band, the band origin and the rotational constants are determined to be Tv = 14383.2533(28) cm−1, A = 287316(33), (B + C)/2 = 16712.8(48), and (B − C)/2 = 532.0(70) MHz. Dispersed fluorescence spectra of the HSO radical were also observed, where the fundamental vibrational frequencies of the ν1 and ν2 modes for the X˜ state have been determined experimentally for the first time.