Rotational Absorption Spectrum of HDO

The 22−21, 30−31, 4−3−31, and the 50−51 rotational absorption transitions of HDO have been observed and identified on the basis of their Stark effect. By comparing the theoretical and experimental Stark shift, the dipole moment for all these transitions has been measured as 1.84±.01. The effective HOD angle is also determined as 104°±30′ and the parameter of asymmetry, k, as about −0.696. The line breadth Δν at one atmosphere is 0.38±0.04 cm−1. None of these quantities is in disagreement with independent determinations.