Knowledge Bank

The spectrum of oxygen-18 enriched water vapor, was recorded between 4 400 and 6 $100cm-1$ with the aid of a Fourier transform $spectrometer1$. Its analysis allowed to determine 60 energy levels of the (0 3 0) vibrational state of $H2\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}0$, 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 $H2\mathrm{<mrow\; data-mjx-texclass="ORD">10</mrow>}0$. This spectrum should be of interest for atmospheric studies.