Line shape of the far-wing beyond the band head of the CO2ν3 band

Carbon dioxide is one of the most important trace gases in the terrestrial atmosphere. The spectral data required in remote sensing are the spectral parameter of each absorption line and a line shape model. This paper describes the absorption properties of CO2 near 2400 cm−1; these properties are of interest to those in the atmospheric temperature sounding field. The shape of the far-wing of N2- and O2-broadened CO2 lines was investigated in the 2200-2500 cm−1 spectral region in a temperature range of atmospheric interest (230-318 K). We focused on the higher rotational quantum number of the R-branch in the ν3 band, where the effect of the far-wing is enhanced. The effect of the far-wing has been studied extensively by others, since the CO2ν3 band is known to exhibit sub-Lorentzian behavior. Here, we show the observed spectra along with calculated spectra for five temperatures. We used first-order line-mixing and the χ-factor, which accounts for the effect of the far-wing, to create the calculated spectra. Our results provide new knowledge of quantum interference of the spectral line in the ν3 band of CO2.