AIR-BROADENED LORENTZ HALFWIDTHS IN THE $\nu_{4}$ BAND OF $^{13}CH_{4}$USING A FOURIER TRANSFORM SPECTROMETER
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Date
1987
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
Room-temperature air-broadened Lorentz halfwidths for more than 150 transitions (for $J \leq 15$) in the $\nu_{4}$ fundamental of $^{13}CH_{4}$ between 1200 and $1380 cm^{-1}$ have been determined by analyzing $0.01-Cm^{-1}-1$ resolution spectra recorded with the Fourier transform spectrometer in the McMath telescope of the National Solar Observatory on Kitt Peak. A 99\% $^{13}C$-enriched $^{13}CH_{4}$ sample diluted to *** 0.5\% by mixing the sample with approximately 200, 350 and 505 Torr of dry air was used in a 50-cm long absorption cell. The halfwidths were determined using nonlinear least-squares spectral curve fitting. The measured air-broadened halfwidths are compared with values determined previously for several transitions in the same band using a tunable diode laser spectrometer $system.^{1}$ Comparisons with identical transitions in the $\nu_{4}$ band of $^{12}CH_{4}$ will also be made.
Description
$^{1}$ V. Malathy Devi, C.P. Rinsland, M.A.H. Smith and D.C. Benner, Appl. Optics, 24. 3321-3322 (1985).
Author Institution: Department of Physics, College of William and Mary; Atmospheric Sciences Division, Mail Stop 401A, NASA Langley Research Center
Author Institution: Department of Physics, College of William and Mary; Atmospheric Sciences Division, Mail Stop 401A, NASA Langley Research Center