Improved line list of 12CH4 in the 4100–4300 cm−1 region A. A. Rodina, A. V. Nikitin, L. Manceron [et al.]
Material type: ArticleContent type: Текст Media type: электронный Subject(s): метан | спектральные линииGenre/Form: статьи в журналах Online resources: Click here to access online In: Journal of Quantitative Spectroscopy and Radiative Transfer Vol. 279. P. 108021Abstract: Four spectra of methane in natural isotopic abundance in the 4100-4300 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 (CH4)-C-12 covering the same region were obtained at 100-123 K for different pressures, 93 m path length at Synchrotron SOLEIL in Paris for different pressures and were used to measure low-J lines. Spectra of (CH4)-C-12 and (CH4)-C-13 obtained at 80 K at JPL in Pasadena were used for additional frequency calibrations. Line positions and intensities were retrieved by non-linear least-squares curve-fitting procedures and analyzed using effective Hamiltonian and effective dipole transition moment models. A new measured line list contains positions and intensities for 12,378 features. Quantum assignments were made for more than 11,520 new transitions, which represent similar to 99% of the integrated line intensity observed in this region. Some of 4556 hot band transitions for (Dyad - Tetradecad) system were assigned. The resulting list of lines is significantly more accurate than previous empirical compilations. All assigned 6963 line positions were fitted to RMS standard deviations of 0.0015 cm(-1). The sum of the observed intensities between 4100 and 4300 cm(-1) falls within 5% of the predicted value from ab initio variational calculations reported in the TheoReTS database (http: //theorets.univ-reims.fr ; http://theorets.tsu.u). (C) 2021 Elsevier Ltd. All rights reserved.Библиогр.: 83 назв.
Four spectra of methane in natural isotopic abundance in the 4100-4300 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 (CH4)-C-12 covering the same region were obtained at 100-123 K for different pressures, 93 m path length at Synchrotron SOLEIL in Paris for different pressures and were used to measure low-J lines. Spectra of (CH4)-C-12 and (CH4)-C-13 obtained at 80 K at JPL in Pasadena were used for additional frequency calibrations. Line positions and intensities were retrieved by non-linear least-squares curve-fitting procedures and analyzed using effective Hamiltonian and effective dipole transition moment models. A new measured line list contains positions and intensities for 12,378 features. Quantum assignments were made for more than 11,520 new transitions, which represent similar to 99% of the integrated line intensity observed in this region. Some of 4556 hot band transitions for (Dyad - Tetradecad) system were assigned. The resulting list of lines is significantly more accurate than previous empirical compilations. All assigned 6963 line positions were fitted to RMS standard deviations of 0.0015 cm(-1). The sum of the observed intensities between 4100 and 4300 cm(-1) falls within 5% of the predicted value from ab initio variational calculations reported in the TheoReTS database (http: //theorets.univ-reims.fr ; http://theorets.tsu.u). (C) 2021 Elsevier Ltd. All rights reserved.
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