Calculation of the Emission Characteristics of Thermally Nonequilibrium CO₂ Gas in the Range of 3200–5400 cm^–1 Using the Line-by-Line and Statistical Narrow-Band Models

A method for calculating the absorption and emission characteristics of CO₂ in the range from 3200 to 5400 cm^–1 with allowance for the effect of thermal nonequilibrium has been presented. A series of calculations using line-by-line (LBL) and statistical narrow-band (SNB) models has been performed at various pressures, spectral regions, layer thicknesses, temperatures, and molar fractions of CO₂. The developed method shows good agreement between the LBL and SNB models and satisfactorily agrees with experimental data when calculating the transmission capacity. In the considered range, the nonequilibrium in rotational temperature has virtually no effect on the radiative characteristics, unlike translational and vibrational temperatures, which have a significant effect on the nonequilibrium Planck function. The resulting methodology can be used for calculations when studying the problem of global warming.