Vibrational analysis of an electronic emission spectrum of sulfur fluorides (32SF2 and 34SF2)

Abstract

An electronic emission spectrum of SF{sub 2} extending from 5,500 to 8,500 {angstrom} is observed during the reactions of F{sub 2} with CS{sub 2}, OCS, and sulfur vapor. Long vibrational band progressions of 355 {plus minus} 2 cm{sup {minus}1} and short progressions of 838 {plus minus} 2 cm{sup {minus}1} are definitively assigned to v{sub 2}{double prime} and v{sub 1}{double prime}, respectively. Isotopic substitution of CS{sub 2} with sulfur-34 has allowed a tentative assignment of the third ground-state frequency, v{sub 3}{double prime} = 817 {plus minus} 6 cm{sup {minus}1}, and the electronic origin, 18,123 {plus minus} 1,000 cm{sup {minus}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. 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.