PRESSURE BROADENING IN THE $^{13}C^{16}O$ 2-0 BAND
Loading...
Date
1997
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
$N_{2}$ induced pressure broadening in the ${^{13}}C{^{16}}O$ 2-0 band around $4167 cm^{-1}$ was investigated using Fourier Transform Spectroscopy. The spectra were recorded with a sample of 99% isotopically pure ${^{13}}CO$ in a White-type absorption cell at a resolution of $0.005 cm^{-1}$. Voigt profiles convolved with the FTS apparatus function were fitted to the observed $lineshapes^{h}$, and Lorentzian HWHM were determined as function of $N_{2}$ pressure. Pressure broadening coefficients for m between -33 and +34 were obtained with uncertainties of 5.8%$^{i}$. The results are compared to $N_{2}$ broadening coefficients obtained from simultaneous measurements in the 2-0 band of ${^{12}}CO$. While the latter values agree well with those published earlier, those of ${^{12}}CO$ are systematically lower by 5--7% compared to ${^{12}}CO$. This indicates that in spectroscopic databases the pressure broadening of ${^{13}}CO$ is significantly overestimated. This is most important since recent $work^{j}$ shows that the ${^{13}}CO/{^{13}}CO$ mixing ratio is an indicator of stratospheric $O_{3}$ depletion chemistry.
Description
$^{h}$K. Chance, Smithsonian Center for Astrophysics, Cambridge, USA. Personal communication (1995). $^{i}$S. Voigt et. al., J. Mol. Spectrose. 180,359(1996). $^{j}$C. A. Brenninkmeijer et al., Geophys. Res. Lett. 23(16),2125(1996).
Author Institution: Institute of Environmental Physics, University of Bremen
Author Institution: Institute of Environmental Physics, University of Bremen