Pure rotational spectrum of hydrogen deuteride by far-infrared Fourier transform spectroscopy

The far-infrared spectrum of HD from 170 to 350 cm-1 is measured with a frequency accuracy of few parts in 10(7) by means of Fourier transform spectroscopy. A general fit including other existing data provides values for B0, D0, and H0 ground-state rotational constants with almost two orders of magnitude improved accuracy.