Electronic transitions of S2− and S3− in neon matrixes

The sulfur View the MathML sourceSn-n = 2, 3 anions produced in a hot cathode discharge ion source were mass-selected and embedded in a neon matrix at 6 K. A long progression with the excitation of up to 12 vibrational quanta is observed in the A 2Πu ← X 2Πg electronic spectrum of View the MathML sourceS2-, with the onset at 467.1 nm. The inferred spectroscopic constants in the A 2Πu state are: ν0−0 = 21,407 ± 4 cm−1, View the MathML sourceω0′=328.4±1 cm−1, View the MathML sourceω0′x0′=2.4±0.1 cm−1. The electronic spectrum of View the MathML sourceS3- in a neon matrix exhibits a rich vibrational structure with a bimodal intensity distribution. This results from the overlap of two electronic transitions, View the MathML sourceC∼2A2←X∼2B1 and (View the MathML sourceD∼ or View the MathML sourceE∼) ← View the MathML sourceX∼2B1, with origins at 701.3 and 619.1 nm. The frequencies (cm−1) of the totally symmetric modes ν1 and ν2 are 466, 184 in the View the MathML sourceC∼2A2 and 446, 177 in the (View the MathML sourceD∼ or View the MathML sourceE∼) states.