High resolution pure rotational spectrum of water vapor enriched by H 217O and H 218O

The pure rotational spectrum of a mixture of H ₂¹⁶O, H ₂¹⁷O and H ₂¹⁸O between 50 and 730 cm ^-1 was recorded on the Fourier transform spectrometer at the University of Oulu. The resolution achieved was about 0.010 cm ^-1 and the precision of the unblended lines was better than 0.001 cm ^-1. About 1100 lines were assigned. The measured line positions of H ₂¹⁷O and H ₂¹⁸O were compared with the values derived from the rotation and distortion constants given in the literature.