MicroWave Spectroscopy Laboratory

Main directions of activity Studies of the molecular spectra Water vapor continuum origin

Water vapor continuum origin

Our study of water vapor continuum spectrum within a pure rotational band of H2O molecule [Ref. 3, 2017] led to the conclusion that its origin cannot be fully explained by dimers within the traditional approach. We re-analyzed available experimental data about the continuum in fundamental vibrational bands and found the same problem: If the total number of dimers is limited by the (well known) second virial coefficient of water vapor equation of state, then dimeric absorption models cannot reproduce the amplitude and in some ranges the shape of observed continuum. The “excess” continuum constitutes from 20 to 50 % of the observed one. We demonstrated that the problem can be easily resolved within our approach to real gas spectra analysis if super-Lorentzian wings of monomer lines (resonance transitions of monomolecular states) are taken into account. See [Ref. 4, 2017] and references therein for more details.

   Institute of Applied Physics of the Russian Academy of Sciences
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