Comparison of profile models for water vapor absorption lines
T.M. Petrova, A.M. Solodov, A.P. Shcherbakov, V.M. Deichuli, A.A. Solodov, Yu.N. Ponomarev
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: absorption line profile, water molecule, Fourier spectrometry
Abstract
The absorption spectra of a water molecule perturbed by argon pressure were measured in the 6700-7650 cm-1 region. The spectra were recorded at an IFS 125HR Fourier spectrometer with a high signal-to-noise ratio at a room temperature with a spectral resolution of 0.01 cm-1. The argon pressure was varied from 0 to 0.9 atm. Using three models of the line profile (the traditional Voigt profile, the quadratic Voigt profile depending on the velocity of the absorbing molecule, and the Hartmann-Tran profile), the parameters of the absorption lines of the water molecule were obtained. It is shown that the use of the HTP profile gives better agreement with the experimental data. For mass measurements at pressures above 300 mbar, it is suggested to use a relatively simple Voigt profile which depends on the velocity of the absorbing molecule.
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