High-Temperature Spectral Absorption of the 4.3-Micron CO2 Band

The absorption coefficients of the ν3, 4.3-μ CO2 band were measured over a temperature range of about 1200° to 2400°K at various pathlengths. The hot CO2 sample was investigated in the exhaust jet of a small supersonic burner, while the jet composition was obtained using a radiation temperature measurement and a simple thermochemical calculation. The present experimental results are compared with existing experimental values and theoretical calculations. The results indicate that above 2000°K a weak line approximation can be used to describe the absorption or emission of the band. The apparent integrated band intensity of the CO2 fundamental as a function of temperature is also reported and discussed in relation to other measurements.