Analyses and modeling of the 12CH4 spectrum at 80 K between 6539 and 6800 cm−1. (January 2016)

• Record Type: Journal Article
• Authors: Nikitin, A.V.; Rey, M.; Tashkun, S.A.; Kassi, S.; Mondelain, D.; Campargue, A.; Tyuterev, Vl.G.
• Is Part Of: Journal of quantitative spectroscopy & radiative transfer. Volume 168(2016:Jan.)
• Page Start: 207
• Page End: 216
• Publication Date: 2016-01
• Subjects: High resolution spectra -- Methane -- Icosad of 12CH4 -- High-order Contact Transformations -- Vibration-rotation states -- Intensities -- Titan; Spectrum analysis -- Periodicals; Radiation -- Periodicals; Analyse spectrale -- Périodiques; Rayonnement -- Périodiques; Radiation; Spectrum analysis; Periodicals; 543.0858
• DOI: 10.1016/j.jqsrt.2015.09.014
• Languages: English
• ISSNs: 0022-4073

Abstract

Abstract: Accurate rovibrational analysis of the lower part of the Icosad 12 CH4 spectrum in the 6539–6800 cm −1 region is reported. The analysis uses the WKLMC experimental line list previously obtained in Grenoble by Cavity Ring Down Spectroscopy and Differential Absorption Spectroscopy at T =80 K. Based on an ab initio potential energy surface, the full Hamiltonian of methane nuclear motion was reduced to an effective Hamiltonian using high-order Contact Transformations method with a subsequent empirical optimization of parameters. About 2445 experimental line positions were fitted with RMS standard deviations of 0.005 cm −1 and 1644 line intensities were modeled using effective dipole moment with the RMS deviation of 11.5%. Twenty five vibrational energy levels of the lower part of the Icosad were determined. Highlights: 12 CH4 line list at 80 K is theoretically modeled in the 6439–6800 cm −1 region. 2443 experimental line positions are reproduced with a 0.005 cm −1 rms . 1644 experimental line intensities at 80 K are modeled with 11% rms. The list of assigned lines with intensities at 80 K is provided. 25 Vibrational energy levels of the lower part of the Icosad are determined.