Narrowing and broadening parameters for H2O lines perturbed by helium, argon and xenon in the 1170-1440 cm-1 spectral range

International audienceCollision effects on water vapor at low concentration in mixture with noble gases (helium, argon and xenon) have been studied by Fourier transform spectroscopy in a pressure range where line narrowing by dynamic confinement (Dicke effect) and collision broadening are observable i.e. when the Voigt function cannot reproduce the observed profiles. Precise values of the broadening parameter have been obtained for P and Q branches of the H2O υ band taking into account the molecular confinement (Hard or Soft collisions). The broadening parameter value derived from a Voigt profile for H2O lines perturbed by helium is to small about 10 % compared with the values determined with the soft or hard collision model. For H2O lines perturbed by argon or xenon this difference can reach more than 50 % for the narrowest lines