Far-infrared absorption spectra of water vapor H216O and isotopic modifications

Far-infrared absorption spectra of H₂¹⁶O, H₂¹⁸O, H¹⁶OD, H¹⁸OD, D₂¹⁶O, D₂¹⁸O have been observed between 10 and 40 cm^?1 at a resolution of 0.07 cm^?1. Experimental and calculated line positions agree within the accuracy of the experiment (±0.003 cm^?1). The relative intensities of type a and type b transitions of H¹⁶OD and H¹⁸OD are used to estimate the ratio $\text{μ}{}_{\mathrm{a}}\text{μ}{}_{\mathrm{b}}$.