EXPERIMENTAL-DETERMINATION OF LINE STRENGTHS FOR SELECTED CARBON-MONOXIDE AND CARBON-DIOXIDE ABSORPTION-LINES AT TEMPERATURES BETWEEN 295 AND 1250 K

Fourier transform infrared absorption spectroscopy has been used for t he determination of the line strengths of 41 CO and CO2 absorption Lin es at temperatures between 295 and 1250 K. The CO vibrational-rotation al lines were from the P branch of the fundamental absorption band (21 50-1950 cm(-1)) while the CO2 vibrational-rotational lines were from t he far wing of the R branch of the upsilon(3) fundamental band (2395-2 380 cm(-1)). The intensities of the lines were measured from absorptio n spectra recorded in a high-temperature gas cell containing known con centrations of CO/CO2/N-2 gas mixtures at atmospheric pressure. Absorp tion spectra were recorded through the cell with the use of a moderate -resolution Fourier transform infrared spectrometer. The absorption sp ectra were mathematically corrected for distortions resulting from the finite resolution of the spectrometer and for peak overlap. Line stre ngth measurements were made from the corrected peaks by using the Boug uer-Lambert law and assuming a Lorenztian line profile. The experiment ally obtained line strengths were evaluated (1) by statistical calcula tions, (2) by consideration of the validity of the Bouguer-Lambert ass umption for these data, (3) by comparison with existing room-temperatu re and high-temperature data, and (4) by comparison with theoretical c alculations. For CO, the statistical analysis suggests that the report ed values have an uncertainty of +/-10-12%, which is similar to the ob served discrepancies with other reported values at room temperature. A t high temperatures, the difference between these data and previously reported data and theoretical predictions is less than 10%. For CO2, t he statistical uncertainty associated with the fine strength calculati ons is less than 5%, which is also the approximate level of agreement with existing room-temperature data. For lines with m indicies of 65-8 9, at high temperatures, the values reported in this work agree within 5 to 10% of theoretical calculations.