First assignment of the 5ν4 and ν2+4ν4 band systems of 12CH4 in the 6287–6550cm−1 region

Nikitin, A.V.; Thomas, Xavier; Régalia, L.; Daumont, Ludovic; Heyden, P. Von der; Tyuterev, Vladimir G.; Wang, Le; Kassi, S.; Campargue, A.

doi:10.1016/j.jqsrt.2010.08.006

Cited by 62 publications

(30 citation statements)

References 60 publications

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“…However, several thousand weak lines ( o10 À 24 cm À 1 /(molecule cm À 2 ) are still missing between 5500 and 6180 cm À 1 . There are a number of recently published and ongoing studies which will help to improve the near infrared (4800-7700 cm À 1 ) line parameters [109][110][111][112][113][114][115][116][117][118]. For broadening, relatively few ( o3000) direct measurements of widths and pressure shifts are available for methane transitions so that default values for self-and air-broadened widths, air-induced pressure shifts and temperature dependences are applied (similar to those used in earlier versions of GEISA see [119,120].…”

Section: Ch 4 (Molecule 6)mentioning

confidence: 99%

The 2009 edition of the GEISA spectroscopic database

Jacquinet-Husson

Crépeau

Armante

et al. 2011

Journal of Quantitative Spectroscopy and Radiative Transfer

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320

133

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The updated 2009 edition of the spectroscopic database GEISA (Gestion et Etude des Informations Spectroscopiques Atmosphé riques; Management and Study of Atmospheric Spectroscopic Information) is described in this paper. GEISA is a computer-accessible system comprising three independent sub-databases devoted, respectively, to: line parameters, infrared and ultraviolet/visible absorption cross-sections, microphysical and optical properties of atmospheric aerosols. In this edition, 50 molecules are involved in the line parameters sub-database, including 111 isotopologues, for a total of 3,807,997 entries, in the spectral range from 10 À 6 to 35,877.031 cm À 1. The successful performances of the new generation of hyperspectral sounders depend ultimately on the accuracy to which the spectroscopic parameters of the optically active atmospheric gases are known, since they constitute an essential input to the forward radiative transfer models that are used to interpret their observations. Currently, GEISA is involved in activities related to the assessment of the capabilities of IASI (Infrared Atmospheric Sounding Interferometer; http://smsc.cnes.fr/IASI/index.htm) on board the METOP European satellite through the GEISA/IASI database derived from GEISA. Since the Metop-A (http://www.eumetsat.int) launch (19 October 2006), GEISA is the reference spectroscopic database for the validation of the level-1 IASI data. Also, GEISA is involved in planetary research, i.e., modeling of Titan's atmosphere, in the comparison with observations performed by Voyager, or by ground-based telescopes, and by the instruments on board the Cassini-Huygens mission. GEISA, continuously developed and maintained at LMD (Laboratoire de Mé té orologie Dynamique, France) since 1976, is implemented on the IPSL/CNRS (France) ''Ether'' Products and Services Centre WEB site (http://ether.ipsl.jussieu.fr), where all archived spectroscopic data can be handled through general and user friendly associated management software facilities. More than 350 researchers are registered for on line use of GEISA.

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Section: Ch 4 (Molecule 6)mentioning

confidence: 99%

The 2009 edition of the GEISA spectroscopic database

Jacquinet-Husson

Crépeau

Armante

et al. 2011

Journal of Quantitative Spectroscopy and Radiative Transfer

Self Cite

320

133

View full text Add to dashboard Cite

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“…These are based on high sensitivity Direct Absorption Spectroscopy (DAS) or Cavity Ring Down Spectroscopy (CRDS) and are significantly deeper than previous measurements, and include low temperature measurements at ~80 K. In addition, a new methane line list in the 5550 -6236 cm -1 region has been established for the GOSAT project (the GOSAT-2009 list, Nikitin et al, 2010a). There have also been some improvements in identification of methane lines in the 6287 -6550 cm -1 region (Nikitin et al, 2010b).…”

Section: Empirical Line Data and Lower State Energiesmentioning

confidence: 99%

The near-IR spectrum of Titan modeled with an improved methane line list

Bailey

Ahlsved

Meadows

2011

Icarus

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We have obtained spatially resolved spectra of Titan in the near-infrared J, H and K bands at a resolving power of ~5000 using the near-infrared integral field spectrometer (NIFS) on the Gemini North 8m telescope. Using recent data from the Cassini/Huygens mission on the atmospheric composition and surface and aerosol properties, we develop a multiple-scattering radiative transfer model for the Titan atmosphere. The Titan spectrum at these wavelengths is dominated by absorption due to methane with a series of strong absorption band systems separated by window regions where the surface of Titan can be seen. We use a line-by-line approach to derive the methane absorption coefficients. The methane spectrum is only accurately represented in standard line lists down to ~2.1 µm. However, by making use of recent laboratory data and modeling of the methane spectrum we are able to construct a new line list that can be used down to 1.3 µm. The new line list allows us to generate spectra that are a good match to the observations at all wavelengths longer than 1.3 µm and allow us to model regions, such as the 1.55 µm window that could not be studied usefully with previous line lists such as HITRAN 2008. We point out the importance of the far-wing line shape of strong methane lines in determining the shape of the methane windows. Line shapes with Lorentzian, and sub-Lorentzian regions are needed to match the shape of the windows, but different shape parameters are needed for the 1.55 µm and 2 µm windows. After the methane lines are modelled our observations are sensitive to additional absorptions, and we use the data in the 1.55 µm region to determine a D/H ratio of 1.77 ± 0.20 × 10 -4 , and a CO mixing ratio of 50 ± 11 ppmv. In the 2 µm window we detect absorption features that can be identified with the ν 5 +3ν 6 and 2ν 3 +2ν 6 bands of CH 3 D.

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“…These ab initio predictions of the PES and molecular properties for small molecules help resolving many issues related to the analysis of the spectra. 31 Theoretical predictions proved to be very useful for analysis of experimental spectra at high-energy ranges. Obviously a construction of twelve-dimensional surfaces for sixatomic molecules is a considerable challenge for the theory.…”

Section: Introductionmentioning

confidence: 99%

A new accurate ground-state potential energy surface of ethylene and predictions for rotational and vibrational energy levels

Delahaye

Nikitin

Rey

et al. 2014

The Journal of Chemical Physics

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In this paper we report a new ground state potential energy surface for ethylene (ethene) C2H4 obtained from extended ab initio calculations. The coupled-cluster approach with the perturbative inclusion of the connected triple excitations CCSD(T) and correlation consistent polarized valence basis set cc-pVQZ was employed for computations of electronic ground state energies. The fit of the surface included 82,542 nuclear configurations using sixth order expansion in curvilinear symmetry-adapted coordinates involving 2236 parameters. A good convergence for variationally computed vibrational levels of the C2H4 molecule was obtained with a RMS(Obs.-Calc.) deviation of 2.7 cm(-1) for fundamental bands centers and 5.9 cm(-1) for vibrational bands up to 7800 cm(-1). Large scale vibrational and rotational calculations for (12)C2H4, (13)C2H4, and (12)C2D4 isotopologues were performed using this new surface. Energy levels for J = 20 up to 6000 cm(-1) are in a good agreement with observations. This represents a considerable improvement with respect to available global predictions of vibrational levels of (13)C2H4 and (12)C2D4 and rovibrational levels of (12)C2H4.

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First assignment of the 5ν4 and ν2+4ν4 band systems of 12CH4 in the 6287–6550cm−1 region

Abstract: Les refs ne sont pas dans l'ordre…..

Cited by 62 publications

References 60 publications

The 2009 edition of the GEISA spectroscopic database

The 2009 edition of the GEISA spectroscopic database

The near-IR spectrum of Titan modeled with an improved methane line list

A new accurate ground-state potential energy surface of ethylene and predictions for rotational and vibrational energy levels

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