Abstract

Simplified equations are developed for computing the emissivity of the carbon dioxide 4.3-μ band. The harmonic oscillator model is assumed in computing band intensities, but anharmonicity is considered in computing the spectral distribution of emitted radiation. Calculated values of $\overline{S}/d$ and ${{2\alpha }_0}^{\frac{1}{2}}{\overline{S}}^{\frac{1}{2}}/d$ are presented for temperatures ranging from 300° to 3000°K, from which emissivities may be readily computed for a given pressure and optical path in both the weak-line and strong-line approximations. In the absence of significant Doppler broadening, both approximations provide upper limits to the emissivity. Emissivities are also computed for the case of a pure Doppler line shape for temperatures ranging from 300° to 1500°K. Doppler broadening is shown to be an important factor in setting a lower limit to the possible values of emissivity obtained at low pressures and long path lengths. Comparisons are made with published experimental data using the weak-line approximation; in several cases, the strong-line approximation as well as a mixed strong-line–weak-line approximation is also shown. The results of the present work are shown to be in good agreement with published experimental data and in definite disagreement with other theoretical calculations.

© 1963 Optical Society of America

Infrared Emissivity of Carbon Dioxide (2.7-μ Band)*

W. Malkmus
J. Opt. Soc. Am. 54(6) 751-758 (1964)

Emissivity of Carbon Dioxide at 4.3 μ

William O. Davies
J. Opt. Soc. Am. 54(4) 467-471 (1964)

Measurements of Infrared Spectral Emissivities of Hot Carbon Dioxide in the 4.3-μ Region*

Richard H. Tourin
J. Opt. Soc. Am. 51(2) 175-183 (1961)

Spectral Emissivity Calculations by the Statistical Model Applied to the 4.3-μ Bands of CO₂ at High Temperatures

Y. Ben-Aryeh
Appl. Opt. 6(6) 1049-1055 (1967)

Statistical Model Applied to the Region of the ν₃ Fundamental of CO₂ at 1200°K*

U. P. Oppenheim and Y. Ben-Aryeh
J. Opt. Soc. Am. 53(3) 344-350 (1963)