Thumbnail Image



Journal Title

Journal ISSN

Volume Title


Ohio State University

Research Projects

Organizational Units

Journal Issue


In a previous $study^{a}$ we had reported air- and $N_{2}$-broadening and pressure-induced shift coefficients for 46 rovibrational transitions in the $^{12}C^{16}O_{2} 00^{0}1-(10^{0}0-02^{0}1)_{I}$ and $00^{0}1-(10^{0}0-02^{0}1)_{II}$ laser bands near $10 \mu m$ These parameters were determined from spectra recorded with the McMath-Pierce Fourier transform spectrometer (FTS) of the National Solar Observatory on Kitt Peak, Arizona. We now report similar measurements of air- and $N_{2}$-broadening and shifts for the two $^{13}C^{16}C_{2}$ laser bands, plus new determinations of self-broadening and shifts in the $^{12}C^{16}O_{2}$ laser bands. These results were obtained from simultaneous analysis of 30 long-path absorption spectra using a multispectrum $nonlinear least-squares technique^{b}$. In addition to the 10 spectra of air-and $N_{2}$-broadened natural $CO_{2}$ analyzed previously, we have included 20 new spectra recorded at room temperature and $0.005 cm^{-1}$ resolution using the McMath-Pierce FTS. These additional spectra include two low pressure, four air-broadened and four $N_{2}$-broadened spectra obtained with a $90% ^{13}C$-enriched $CO_{2}$ sample and 10 self-broadened spectra obtained with a high purity natural $CO_{2}$ sample. The self-broadened spectra were recorded with pathlengths of 73, 97, 193 and 433 m and $CO_{2}$ pressures varying between 3 Torr and 400 Torr. The $^{13}CO_{2}$ spectra were obtained with a pathlength of 84 m with sample pressures < 4 Torr for the low-pressure spectra and from 100 to 500 Torr for the air- and $N_{2}$-broadened mixtures. By combining the spectra of $^{12}CO_{2}$ and $^{13}CO_{2}$ in the same fit we were able to obtain a consistent set of line parameters for both molecules. The results obtained for the $^{12}CO_{2}$ and $^{13}CO_{2}$ laser bands will be compared with each other, with the values in the HITRAN $database^{c}$, and with available values reported in the literature.


$^{a}$V. Malathy Devi, D. Chris Benner, M. A. H. Smith and C. P. Rinsland, JQSRT 59, 137-149 (1998). $^{b}$D. Chris Benner, C. P. Rinsland, V. Malathy Devi, M. A. H. Smith and D. Atkins, JQSRT 53, 705-721 (1995). $^{c}$L. S. Rothman et al., JQSRT 60, 665-710 (1998).
Author Institution: The College of William and Mary; Department of Physics, The College of William and Mary; Department of Physics, NASA Langley Research Center; Atmospheric Sciences, NASA Langley Research Center; Atmospheric Sciences, California Institute of Technology; Jet Propulsion Laboratory, National Solar Observatory