Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5426948 | Journal of Quantitative Spectroscopy and Radiative Transfer | 2017 | 10 Pages |
â¢5934 line positions and intensities were retrieved in the 5300-5550â¯cmâ1 region.â¢12CH4 line list with assignments was made in the 5300-5550â¯cmâ1 region.â¢2847 experimental line positions were modeled to 0.0025â¯cmâ1.â¢2227 experimental line intensities at 296â¯K were modeled to 8.6%â¯rms.
A new study of 12CH4 line positions and intensities was performed for part of the Tetradecad region between 5300 and 5550â¯cmâ1 using four long path (202â¯m, 602â¯m, 1604â¯m and 1804â¯m) spectra of normal samples of CH4 at different pressures recorded with a Fourier transform spectrometer in Reims, France. Line positions and intensities were retrieved by least square curve-fitting procedures and analyzed using the effective Hamiltonian and the effective dipole moment expressed in terms of irreducible tensor operators adapted to spherical top molecules. An 80â¯K spectrum from JPL of enriched 12CH4 was used for low-J line positions. One other 80â¯K spectrum from JPL of enriched 13CH4 was used to discern the isotopic lines. A new measured linelist contains positions and intensities for 5934 features. Quantum assignments were made for 2847 transitions, which represent â¼90% of the integrated line intensity observed in this region. All assigned line positions and 2227 selected line intensities were fitted with RMS standard deviations of 0.0025â¯cmâ1 and 8.6%, respectively. The sum of observed intensities between 5300 and 5550â¯cmâ1 fell within 2% of the predicted value from ab initio variational calculations.