Infrared and microwave spectra of OCO–HF and SCO–HF

The H–F stretching bands of the OCO–HF and SCO–HF complexes have been studied by optothermal (bolometer-detected) molecular-beam spectroscopy. Both species exhibit spectra of a quasilinear molecule red shifted from free HF by 52.1 and 57.5 cm−1, respectively. The principal band in both molecules is accompanied by a slightly red-shifted doublet-type subsidiary band that can be interpreted as a hot band of a low frequency bending vibration or a K=1 subband of a bent molecule. Accurate doublet splittings in the ground H–F vibrational state have been measured by pulsed-nozzle Fourier-transform microwave spectroscopy.