High Temperature Absorption Spectrum of 4.3 Micron CO2†

The importance of CO2 as an atmospheric molecule makes the obtaining of high precision band parameters for a great number of bands a significant contribution to both theoretical and experimental studies of our atmosphere. Very accurate parameters on the (00011-00001) band of 12C16O2 have been obtained by Pine and Guelachvili. Their measurment was accomplished by combining two spectra, a room temperature Fourier transform spectrum, and a high temperature tunable laser spectrum.1 There have been numerous measurements of other bands of CO2,2,3 but they were made either with lower resolution spectrometers, or near room temperature where fewer rotational lines were excited, resulting in a less accurate determination of band parameters. In this work a high resolution Michelson interferometer was coupled with a high temperature absorption cell4 heated to 800 K to obtain a high resolution (0.007 cm−1), high temperature spectrum of CO2 in the 4.3 micron region.