Improved line list of 12CH4 in the 3760–4100 cm−1 region. (March 2019)

• Record Type: Journal Article
• Authors: Rodina, A.A.; Nikitin, A.V.; Thomas, X.; Manceron, L.; Daumont, L.; Rey, M.; Sung, K.; Tashkun, S.A.; Tyuterev, Vl.G.
• Is Part Of: Journal of quantitative spectroscopy & radiative transfer. Volume 225(2019)
• Page Start: 351
• Page End: 362
• Publication Date: 2019-03
• Subjects: High resolution spectra -- CH4 -- Methane -- Octad -- Long path FTIR -- Vibration-rotation states -- Intensities -- Infrared absorption -- Effective Hamiltonian; Spectrum analysis -- Periodicals; Radiation -- Periodicals; Analyse spectrale -- Périodiques; Rayonnement -- Périodiques; Radiation; Spectrum analysis; Periodicals; 543.0858
• DOI: 10.1016/j.jqsrt.2018.12.034
• Languages: English
• ISSNs: 0022-4073

Abstract

Highlights: 9015 line positions and intensities were retrieved in the 3760–4100 cm −1 region. More than 3500 new assignments were made in the region. 5703 experimental line positions were modeled to 0.00179 cm −1 . 2659 experimental line intensities at 296 K were modeled to 7.46% rms. Abstract: Eight spectra of normal samples of CH4 in the 3760–4100 cm −1 region were recorded by using a Fourier transform spectrometer in Reims, France at long paths (202 m, 602 m, 1604 m and 1804 m) and different pressures. Additional spectra of 12 CH4 covering the same region were obtained at 100 K and very low sample pressures, which was used for low-J line position identification. Line positions and intensities were retrieved by least squares curve-fitting procedures and analyzed using the effective Hamiltonian and the effective dipole. A new measured line list contains positions and intensities for 9000 features. Quantum assignments were made for more than 3500 new transitions, which represent ∼95% of the integrated line intensity observed in this region. The resulting list of lines is much more accurate than the list of lines HITRAN 2016. All assigned 5703 line positions were fitted to RMS standard deviations of 0.0018 cm −1 . The sum of observed intensities between 3760 and 4100 cm −1 fell within 2% of the predicted value from ab initio variational calculations reported in the TheoReTS database (http://theorets.univ-reims.fr ;http://theorets.tsu.ru ).