Photoacoustic spectroscopic studies on a mixture of six CO2 isotopes (12 C16 O2, 12 C18 O2, 13 C 16 O2, 13 C18 O2, 16 O12 C18 O, and 16 O13 C18 O) in the wavelength range of 9–11 μm by use of a home-built high-pressure continuously tunable CO2 laser with a bandwidth of 0.017 cm−1 are discussed. The concentrations of all CO2 isotopes present in the mixture could be determined with good accuracy. Furthermore, the previously unknown absorption cross sections of some important lines of the12 C18 O2, 13 C18 O2, and 16O 13 C18 O isotopes in the 9–11-μm range are reported.
© 1997 Optical Society of America
I. G. Calasso, V. Funtov, and M. W. Sigrist, "Analysis of isotopic CO2 mixtures by laser photoacoustic spectroscopy," Appl. Opt. 36, 3212-3216 (1997)