Diode laser spectroscopy of the SF radical

Abstract

The vibration-rotation spectra of the SF radical were observed by an infrared diode laser spectrometer. The SF radical was generated directly in a cell by glow discharge in a mixture of carbonyl sulfide and carbon tetrafluoride. Zeeman modulation and discharge current modulation were employed to discriminate SF lines from many lines of the reactants and other products. Thirty two lines were assigned to the v = 1 ← 0 and 2 ← 1 bands of both 2 Π 1 2 and 2 Π 3 2 spin states. A least-squares analysis of all the assigned lines provided precise values for molecular parameters in v = 1 and 2 and the two band origins, where ground-state constants were constrained to microwave results. The harmonic frequency ω e was thus determined to be 837.6418(13) cm −1, and the equilibrium bond length r e was calculated from the B e rotational constant to be 1.596 244(22) Å with the error in parentheses, which included 2.5 standard deviations and the uncertainty of Planck's constant.