H218O: The (030), (110), and (011) interacting states. Line positions and intensities for the 3ν2, ν1 + ν2, and ν2 + ν3 bands

Abstract

The spectrum of oxygen-18 enriched water vapor was recorded between 4400 and 6100 cm−1 with the aid of a Fourier transform spectrometer. Its analysis allowed the determination of 60 energy levels of the (030) vibrational state of H218O and improvements in the knowledge of the energy levels belonging to the (110) and (011) vibrational states of this molecule. A fit of 330 rotational levels of the (030), (110), and (011) 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 3ν2, ν1 + ν2, and ν2 + ν3 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 3ν2, ν1 + ν2, and ν2 + ν3 bands of H218O. This spectrum should be of interest for atmospheric studies.