Infrared Spectroscopy of the ν1 Band of Sulfur Tetrafluoride, SF4

Infrared absorption spectra of the ν₁ axial S-F stretching vibrational bands of sulfur tetrafluoride, SF₄, have been recorded and analyzed. A diode-laser jet spectrometer was used to record high-resolution spectra of ³²SF₄, with 87 vibration-rotation lines of the ν₁ fundamental being assigned. Least-squares fitting of the data yielded a precise vibrational band origin, as well as rotational parameters for the upper state. In addition, lower-resolution spectra of a static sample of SF₄ held at room temperature were recorded using a Fourier transform (FTIR) spectrometer. The progressions of prominent features observed in the room-temperature FTIR spectra are attributed to summation bands arising from ν₁ transitions from excited vibrational levels of the low-frequency ν₄ manifold of both ³²SF₄ and ³⁴SF₄.