THE SECOND TRIAD OF INTERACTING STATES OF $H_{2}{^{1}8}O$. LINE POSITIONS AND INTENSITIES FOR THE $3\nu_{2}, \nu_{1}+\nu_{2}$ AND $\nu_{2} + \nu_{3}$ BANDS

$^{1}$J.W. Brault, Proceedings of JOSO Workshop (1978). In Osservatori e memorie dell' Osservatorio Astrophysico di Arcetri 106, 33 (1979).Author Institution: Laboratoire de Physique Mol\'{e}culaire et d'Optique Atmosph\'{e}rique; Laboratoire de Physique Mol\'{e}culaire et d'Optique Atmosph\'{e}rique; Laboratoire de Physique Mol\'{e}culaire et d'Optique Atmosph\'{e}rique; Laboratoire de Physique Mol\'{e}culaire et d'Optique Atmosph\'{e}riqueThe spectrum of oxygen-18 enriched water vapor, was recorded between 4 400 and 6 $100 cm^{-1}$ with the aid of a Fourier transform $spectrometer^{1}$. Its analysis allowed to determine 60 energy levels of the (0 3 0) vibrational state of $H_{2}{^{18}}0$, and to improve the knowledge of the energy levels belonging to the (1 1 0) and (0 1 1) vibrational states of this molecule. A fit of 330 rotational levels of the (0 3 0), (1 1 0) and (0 1 1) states was performed using 54 effective constants and taking into account the Coriolis-type and Fermi-type interactions. Moreover, 853 line intensities belonging to the $3\nu_{2}, \nu_{1} + \nu_{2}$ and $\nu_{2} + \nu_{3}$ bands were measured. The constants involved in the rotational expansion of the transformed transition moment operator corresponding to these bands were determined through a fit of these line intensities. The constants obtained were then used to compute the whole spectrum of the $3 \nu_{2}, \nu_{1}+\nu_{2}$ and $\nu_{2}+\nu_{3}$ bands of $H_{2}{^{10}}0$. This spectrum should be of interest for atmospheric studies