Broadening of CO₂ lines in the 4.3 μm region by H₂O

Transmission spectra of CO₂ highly diluted in water vapor have been recorded at 50 and 95 °C for four pressures between 0.02 and 0.1 atm using a high resolution Fourier Transform spectrometer. The collisional (Lorentz) widths of many lines of the ν₃ band (and of some of the ν₃ + ν₂ − ν₂ hot band) have been retrieved from each spectrum through fits using Voigt line shapes. Our result are about 4% lower than the values recommended in a previous study but they confirm the relative variations of the line broadening on the rotational quantum numbers. We also provide the first determination of H₂O-induced line shifts of CO₂ lines.