Measurements and calculations of CO2-broadening and shift coefficients of water vapor transitions in the 5150–5550 cm−1 spectral region

Abstract

The high-resolution H2O absorption spectra induced by CO2 pressure have been recorded using a Bruker IFS 125 HR FTIR spectrometer at room temperature in the 5150–5550 cm–1 spectral region. A multispectrum fitting procedure has been applied to these spectra to recover the spectral line parameters using the speed-dependent Voigt profile. The water vapor line broadening and shift coefficients for lines of two vibrational bands ν2+ν3 and ν1+ν2 were obtained. An uncertainty of the broadening coefficients for the unblended H2O absorption lines was estimated to be 2–3%. The calculations of line-broadening and line-shifting parameters were performed using the semi-empirical method which is based on the impact theory and enables a realistic prediction modified by introducing additional parameters obtained by using empirical data. The root mean square deviations of measured and calculated line widths and shifts were 0.0086 and 0.0053 cm−1 atm−1, respectively.