Calculation of infrared radiation scattered by a gas-powdered medium

Using the Widder method, the reflectivity of a semiinfinite layer of a gas-powdered medium is determined with a radiation-absorption law of a gas medium corresponding to the statistical model of Goody (1964). It is shown for the example of the CO2 4.3-micron band that for a particle attenuation coefficient k greater than 1/m the particles can substantially affect thermal emission in a given spectral interval. This fact must be taken into account in temperature measurements from infrared radiation in bands of powdered gases. Results are given on calculations of the reflectivity for various parameters of statistical band models and for various values of the photon-survival probability following scattering by the medium particles.