H2O absorption spectra in the IR region

The absorption spectra of the mixtures of water vapor and air at different partial pressures of both gases have been recorded using a Fourier spectrometer IFS 125 HR in the 3500−5670 cm^–1 spectral region. The multispectrum fitting procedure has been applied to these spectra to recover the spectral line parameters. The traditional Voigt and quadratic speed-dependent Voigt ones were used. Particular attention was paid to the analysis of the broadening and shift coefficients of the H₂O absorption lines. The significant difference between the obtained and literary data was shown. The atmospheric transmission was simulated with the H₂O absorption lines from the HITRAN and GEISA spectroscopic databases and with new lines parameters obtained in this work.