Infrared Radiant Spectrum Calculation of the Gas in the Atmosphere Based on Physical Model

摘要

This paper proposes a theoretical method based on physical model to calculate infrared (IR) radiation spectrum. IR physics establishes that emission abilities of objects are measured by emissivity, while the emissivity of objects is based on the emissivity of a blackbody. Planck formula shows how to calculate the spectral energy density of a blackbody, and IR radiation spectrum of a sample can be easily obtained if its emissivity is known. Kirchhoff’s law shows the emissivity of an object is equal to its absorptance at the same conditions. By calculating the absorption coefficient using line-by-line model, the absorptance can be achieved through the relationship between them. The performance data of the technique is from public databases.