CO2 absorption in band wings in near IR

Abstract

The CO2 absorption was measured in the 7000 and 8000 cm–1 regions. The absorption coefficients were calculated using the asymptotic line wing shape theory. Line shape parameters were found from fitting to experimental data. The calculation results agree well with the measurement data. According to the line wing theory, the absorption in the band wings is caused by the wings of strong lines of an adjacent band. Within these assumptions, experimental and calculated data on the CO2 absorption coefficient in the band wings in the 7000 and 8000 cm–1 regions can provide information on the line shape at frequency detuning from several tens to several hundreds of half-widths. The results support the hypothesis that line shape parameters in the line wings related to transitions with the same initial state are close to each other. Deviations from a Lorentzian profile are found for some CO2 bands and turn out different for the wings of different bands