Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5415771 | Journal of Molecular Spectroscopy | 2007 | 12 Pages |
Abstract
This study provides the first direct experimental measurements of the off-diagonal relaxation matrix element coefficients for line mixing in air-broadened methane spectra for any vibrational band and the first off diagonal relaxation matrix elements associated with line mixing for pure methane in the ν2 + ν3 band of 12CH4. The speed-dependent Voigt profile with line mixing is used with a multispectrum nonlinear least squares curve fitting technique to retrieve the various line parameters from 11 self-broadened and 10 air-broadened spectra simultaneously. The room temperature spectra analyzed in this work are recorded at 0.011 cmâ1 resolution with the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory, Kitt Peak, Arizona. The off-diagonal relaxation matrix element coefficients of ν2 + ν3 transitions between 4410 and 4629 cmâ1 are reported for eighteen pairs with upper state J values between 2 and 11. The observed line mixing coefficients for self broadening vary from 0.0019 to 0.0390 cmâ1 atmâ1 at 296 K. The measured line mixing coefficients for air broadening vary from 0.0005 to 0.0205 cmâ1 atmâ1 at 296 K.
Related Topics
Physical Sciences and Engineering
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Physical and Theoretical Chemistry
Authors
Adriana Predoi-Cross, Anildev V. Unni, Henry Heung, V. Malathy Devi, D. Chris Benner, Linda R. Brown,