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.