15min:

V. MALATHY DEVI, D. CHRIS BENNER, Dept. of Physics, The College of William and Mary, Williamsburg, VA 23187; K. SUNG, L. R. BROWN, T. J. CRAWFORD, SHANSHAN YU, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109; M. A. H. SMITH, Science Directorate, NASA Langley Research Center, Hampton, VA 23681; A. W. MANTZ, Dept. of Physics, Astronomy and Geophysics, Connecticut College, New London, CT 06320.

Complete and accurate information on line shape parameters of 2 ₃ methane transitions for air broadening as a function of temperature is critical not only for the correct interpretation of the observed atmospheric spectra but also for the development of a reliable theoretical model. For this reason, we obtained a series of high-resolution, high S/N spectra of high-purity ¹²CH₄ and ¹²CH₄ broadened with dry air at temperatures in the 130 to 295 K range using the Bruker IFS 125HR Fourier transform spectrometer at JPL. Two absorption cells were used in the experiment, a White cell with path length of 13 m for room temperature spectra and a 21 m Herriott cell for cold sample spectra. The 15 spectra used in the analysis consisted of 3 low pressure (0.26 to 2.57 Torr) spectra with pure ¹²CH₄ and 12 air-broadened spectra with total sample pressures of 79-805 Torr and volume mixing ratios of methane between 0.23 and 1%. A multispectrum least-squares fitting technique was employed to fit all 15 spectra simultaneously. Preliminary results for select R(J) manifolds will be presented.