Far-Infrared and υ₂ Vibration-Rotation Spectrum of Thioformaldehyde and Infrared Spectrum of Thioglyoxal

The ν₂ fundamental band at 1455 cm^-1 and pure rotational spectrum of thioformaldehyde in the range 16-60 cm^-1 have been recorded at 0.003 cm^-1 resolution using a Fourier transform infrared spectrometer. More than 1300 transitions have been assigned with the help of an interactive Loomis-Wood fitting program and improved ground state constants have been obtained. The pure rotational spectrum of the ³⁴S isotopomer has been observed in natural abundance and 126 transitions were assigned. Rotational and centrifugal distortion constants have been obtained for ν₂ and the band origin has been determined as 1455.49505(56) cm^-1. The low-resolution gas-phase spectrum of thioglyoxal has been recorded in the range 4000-650 cm^-1 and the stronger bands have been assigned. The CO stretching mode, ν₃, has been investigated at 0.003 cm^-1 resolution.