VIBRATIONAL ANALYSIS OF AN ELECTRONIC EMISSION-SPECTRUM OF (SF2)-S-32 AND (SF2)-S-34

An electronic emission spectrum of SF2 extending from 5500 to 8500 Å is observed during the reactions of F2 with CS2, OCS, and sulfur vapor. Long vibrational band progressions of 355 ± 2 cm-1 and short progressions of 838 ± 2 cm-1 are definitively assigned to v2″ and v1″, respectively. Isotopic substitution of CS2 with sulfur-34 has allowed a tentative assignment of the third ground-state frequency, v3″ = 817 ± 6 cm-1, and the electronic origin, 18 123 ± 1000 cm-1. Ground-state frequencies and their isotopic shifts compared very well with those obtained in infrared absorption experiments by other workers. Estimates of the anharmonicities of the ground-state frequencies are presented. Weak bands lying 243 ± 6 cm-1 to the blue of the strongest bands are ascribed to the v2′ frequency. Results of first principles electronic energy calculations are presented, showing that two low-lying singlet electronic states are in the energy range of this emission spectrum. A discussion is presented relating the possible activity of the asymmetric stretch and the nature of the excited electronic state. The true multiplicities of the electronic states are undetermined and unaddressed. Reaction of CS2 with F2 produces SF2* together with an unknown feature displaying overlapping vibrational bands, 310 ± 30 cm-1 apart, extending from 7000 Å into the near-infrared region. Reaction of F2 with SO2 produced no detectable chemiluminescence between 3000 and 8800 Å. © 1990 American Chemical Society.