BROADENING AND SHIFT COEFFICIENTS IN THE $\nu_{3}$ BANDS OF $^{12}C^{16}O_{2}$ AND $^{13}C^{16}O_{2}$
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Date
2002
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Ohio State University
Abstract
In a previous $study^{a}$ we had reported $N_{2}$-broadening and pressure-induced shift coefficients for 34 rovibrational transitions in the $^{12}C^{16}O_{2} \nu_{3}$ fundamental band near $4.3 {\mu}m$. 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 $N_{2}$-broadening and shifts for transitions up to $J^{\prime\prime} = 56$ in the $^{13}C^{16}O_{2} \nu_{3}$ fundamental band, plus determinations of $N_{2}$-broadening coefficients in the $^{13}C^{16}O_{2} \nu_{2} + \nu_{3} - \nu_{2}$ hot band and the $^{13}C^{16}O^{18}O \nu_{3}$ fundamental band. We also made new measurements of $N_{2}$-broadening and pressure-induced shift coefficients for rovibrational transitions up to $J^{\prime\prime} = 46$ in the $^{12}C^{16}O_{2} \nu_{3}$ fundamental band. These results were obtained from simultaneous analysis of five absorption spectra using a multispectrum nonlinear least-squares $technique^{b}$. A 4.08 cm sample cell at room temperature was used to record all of the spectra at $0.003 cm^{-1}$ resolution with the McMath-Pierce FTS. This data set includes one low pressure (0.15 Torr) spectrum obtained with a $90% {^{13}}C$-enriched $CO_{2}$ sample and four spectra of lean mixtures of the same $^{13}CO_{2}$ sample in $N_{2}$. Total pressures of the mixtures were between 101 Torr and 464 Torr. Because of the isotopic sample used, the $\nu_{3}$ fundamental bands of $^{12}CO_{2}$ and $^{13}CO_{2}$ appeared together in the same spectra, and we were able to obtain a consistent set of line parameters for both molecules. The present measurements represent the first experimental determination of $N_{2}$-broadening and pressure-induced shift coefficients in isotopic bands of $CO_{2}$ in the $4.3 {\mu}m$ region. The results obtained for the various bands will be compared with each other, with the values in the HITRAN $database^{c}$, and with available values reported in the literature.
Description
$^{a}$V. Malathy Devi, D. Chris Benner, C. P. Rinsland and M. A. H. Smith, JQSRT 48, 581-590 (1992). $^{b}$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, R. L. Hawkins, R. B. Wattson and R. R. Gamache, JQSRT 48, 537-566 (1992).
Author Institution: Atmospheric Sciences, NASA Langley Research Center; Department of Physics, The College of William and Mary
Author Institution: Atmospheric Sciences, NASA Langley Research Center; Department of Physics, The College of William and Mary