The 2009 edition of the GEISA spectroscopic database Jacquinet-Husson, N.; Crepeau, L.; Armante, R. ...
Journal of quantitative spectroscopy & radiative transfer,
10/2011, Volume:
112, Issue:
15
Journal Article
Peer reviewed
The updated 2009 edition of the spectroscopic database GEISA (Gestion et Etude des Informations Spectroscopiques Atmosphériques; 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
−6 to 35,877.031
cm
−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 Météorologie 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.
► Strong interaction with Earth's and planetary atmospheres remote sensing. ► Improvement of the quality of the direct and inverse planetary atmosphere modeling. ► Evident importance for Research in Climate and Environment.► Promotion and motivation for Research in Spectroscopy (theoretical and experimental).
The Fukushima accident emphasized the fact that ways to monitor in real time the evolution of a nuclear reactor during a severe accident remain to be developed. No fission products were monitored ...during twelve days; only dose rates were measured, which is not sufficient to carry out an online diagnosis of the event. The first measurements were announced with little reliability for low volatile fission products. In order to improve the safety of nuclear plants and minimize the industrial, ecological and health consequences of a severe accident, it is necessary to develop new reliable measurement systems, operating at the earliest and closest to the emission source of fission products. Through the French program ANR « Projet d’Investissement d’Avenir », the aim of the DECA-PF project (diagnosis of core degradation from fission products measurements) is to monitor in real time the release of the major fission products (krypton, xenon, gaseous forms of iodine and ruthenium) outside the nuclear reactor containment. These products are released at different times during a nuclear accident and at different states of the nuclear core degradation. Thus, monitoring these fission products gives information on the situation inside the containment and helps to apply the Severe Accident Management procedures. Analytical techniques have been proposed and evaluated. The results are discussed here.
•Absolute line intensities for the ν4 bands of Trans-HONO and Cis-HONO measured.•Improved line positions using infrared FTS spectra on SOLEIL.•Line list for HONO in the 11 µm infrared region.•For ...cis-HONO, the {41, 51, 61} energy levels are coupled together.
The goal of this work was to update and significantly improve the line lists that have been generated recently for 11 µm bands of the trans- and cis- conformer forms of nitrous acid (HONO) Armante R, Perrin A, Kwabia Tchana F, Manceron L. The ν4 bands at 11 μm: linelists for the trans- and cis- conformer forms of nitrous acid (HONO) in the 2019 version of the GEISA database. Molecular Physics 2021;120:e1951860. That 2019 version of the 11 µm line list was generated using the spectroscopic parameters that were available, at that time, in the literature. During the present study, we used high-resolution Fourier transform spectra recorded at 11 µm to perform a large investigation of line positions and intensities for the ν4 bands of the trans- and cis-conformer of HONO. The resulting set of experimental ν4 (absolute) intensities and of 41 energy levels were used to determine, by least squares fit computations, improved position and intensity parameters for the ν4 bands of the trans- and cis-conformer of HONO. For trans-HONO, the ν4 band appeared not to be perturbed, while for cis-HONO a weak high order B-type Coriolis, coupling together the 41 and 61 energy levels was evidenced for the first time. This new list is of potential interest for the IASI-NG (Infrared Atmospheric Sounding Interferometer - New Generation) instrument which will be launched on board the METOP-SG satellite in 2025.
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•Laboratory far infrared spectra of pure dicyanoacetylene.•First far infrared band intensity measurement.•Global rovibrational analysis and first line list.•Abundance upper limit determination of ...gaseous dicyanoacetylene in Titan’s atmosphere.•Radiative transfer calculation and Cassini-CIRS far infrared observations.
Dicyanoacetylene has not been observed so far in the gas phase in Titan’s atmosphere but this molecule is still on the list of the detected species, on the basis of the correspondence between a solid phase feature measured at 478cm−1 in the laboratory and a spectral feature observed by Voyager. In this work, the infrared spectrum of gaseous C4N2 has been investigated to improve our knowledge of the band intensities and the line parameters for this molecule. Results of previously investigated bands have been revised and the intensity of the ν9 band at 107cm−1, measured for the first time, was found to be the strongest absorption in the whole infrared domain. We have also improved the analysis of the complex rotational and hot band structure of C4N2 in order to obtain the first line lists for both bending modes ν8 and ν9. Using our radiative transfer code including the new line list of the strong ν9 band, we have searched for the signature of C4N2 at 107cm−1 in the atmosphere of Titan utilizing Titan CIRS far infrared spectra. Despite averaging a large number of CIRS spectra at northern latitudes during the very favorable Titan winter, no gaseous C4N2 could be detected. At the 1-σ level we obtain an abundance upper limit of 5.3×10−10 for the limb average which is lower than or comparable to previously inferred values. As a consequence, the absence or very low amount of gaseous C4N2 makes quite puzzling its presence in the solid phase with an abundance compatible with the observed spectral feature at 478cm−1.
We present a new global study of the millimeter, submillimeter and far-infrared (FIR) spectra of dimethylsulfide ((CH3)2S). New microwave measurements have been carried out between 49 and 660 GHz ...using spectrometers in IRA NASU (Ukraine), and PhLAM Lille (France). Pure rotational transitions belonging to the three lowest torsional states (ν11,ν15) = (0,0), (1,0), (0,1) of the molecule as well as to intertorsional transitions (ν11,ν15) = (1,0) ↔ (0,1) observable in the millimeter and submillimeter wave ranges due to intensity borrowing via avoided-crossing interactions were combined with new assignments in the fundamental torsional band (AILES beamline of the synchrotron SOLEIL) and analyzed using a model developed for molecules with two equivalent methyl rotors and C2v symmetry at equilibrium (PAM_C2v_2tops program). The upper limit of the frequency range coverage for the microwave data was extended from 300 GHz to 660 GHz and all symmetry species in the torsional excited states and fundamental torsion band of the molecule were analyzed. The final fit included 87 parameters to give an overall weighted root-mean-square deviation of 0.71 for the dataset with J up to 60 consisting of 22277 microwave line frequencies belonging to the three lowest torsional states (ν11,ν15) = (0,0), (1,0), (0,1) as well as to intertorsional transitions (ν11,ν15) = (1,0) ↔ (0,1) and 5720 FIR line frequencies belonging to the observed fundamental band associated with the methyl-top torsion mode (ν11,ν15) = (0,1) ← (0,0). This investigation presents a twofold expansion in the J quantum number for the ground torsional state (ν11,ν15) = (0,0) and the fundamental torsional band (ν11,ν15) = (0,1) ← (0,0); and significantly extends the analysis for the excited torsional states with one torsional quantum excited (ν11,ν15) = (1,0) and (0,1) for which only 18 transitions with J ≤ 5 were analyzed in previous work.
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•A new global study of the mm, submm and FIR spectra of dimethylsulfide.•Analysis of all symmetry species in the fundamental torsional band of dimethylsulfide.•Performance of PAM_C2v_2tops program with respect to a higher ρ value is tested.
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•Analysis of CD2HOH torsional and rotation–torsion spectra up to K=11 and vt=11.•101 torsional subband identified in the submillimeter wave, terahertz, and FIR spectra.•3271 rotation ...and rotation–torsion transitions assigned up to e1.•1997 rotation–torsion transitions with vt′>2 assigned.•Hindering potential determined fitting 108 torsional subband centers.
The torsional and rotation–torsion spectra of the doubly deuterated species of methanol CD2HOH have been analyzed using submillimeter wave, terahertz, and far infrared spectra. 101 torsional subbands, with subband centers ranging from 2.3 to 626cm−1, were assigned. Analysis of these yielded kinetic energy and hindering potential parameters of the torsional Hamiltonian describing the large amplitude internal rotation of the CD2H methyl group with respect to the hydroxyl group. 3271 rotation and rotation–torsion transitions, involving the 24 torsional levels up to e1 with 3⩽K⩽10, were assigned and fitted approximating the rotational energy of each torsional level with a Taylor-type expansion in J(J+1). The rotational structure of 48 torsional subbands involving torsional levels higher than e1 has also been analyzed. In most cases, only the Q branch could be observed and assigned.
The goal of this study is to achieve absolute line intensities for the strong 5.7 and 3.6
μm bands of formaldehyde and to generate, for both spectral regions, an accurate list of line positions and ...intensities. Both bands are now used for the infrared measurements of this molecule in the atmosphere. However, in the common access spectroscopic databases there exists, up to now, no line parameters for the 5.7
μm region, while, at 3.6
μm, the quality of the line parameters is quite unsatisfactory. High-resolution Fourier transform spectra were recorded for the whole 1600–3200
cm
−1 spectral range and for different path-length-pressure products conditions. Using these spectra, a large set of H
2CO individual line intensities was measured simultaneously in both the 5.7 and 3.6
μm spectral regions. From this set of experimental line strength which involve, at 5.7
μm the
ν
2 band and, at 3.6
μm, the
ν
1 and
ν
5 bands together with nine dark bands, it has been possible to derive a consistent set of line intensity parameters for both the 5.7 and 3.6
μm spectral regions. These parameters were used to generate a line list in both regions. For this task, we used the line positions generated in Margulés L, Perrin A, Janeckovà R, Bailleux S, Endres CP, Giesen TF, et al. Can J Phys, accepted and Perrin A, Valentin A, Daumont L, J Mol Struct 2006;780–782:28–42 for the 5.7 and 3.6
μm, respectively. The calculated band intensities derived for the 5.7 and 3.6
μm bands are in excellent agreement with the values achieved recently by medium resolution band intensity measurements. It has to be mentioned that intensities in the 3.6
μm achieved in this work are on the average about 28% stronger than those quoted in the HITRAN or GEISA databases. Finally, at 3.6
μm the quality of the intensities was significantly improved even on the relative scale, as compared to our previous study performed in 2006.
Diacetylene (C4H2) has been observed in various astrophysical environments in the infrared range through the bending modes ν8 at 628.0 and ν9 at 220.1cm−1. Accurate intensity measurements of both ...modes are necessary to obtain precise abundance determination. Laboratory spectra covering both bending modes have been recorded with a pure diacetylene sample. Precise band intensities have been measured showing large discrepancies compared to previous studies, reaching a factor 2.3 for the ν9 band and a smaller difference of 20% for the ν8 band. Consequences on the determination of abundances of diacetylene in Titan׳s atmosphere are discussed.
•Infrared spectra in far and mid-infrared of diacetylene with a pure sample.•Large revision of previously measured band intensities.•Consequences on abundance determination in astrophysical environments and in particular Titan׳s atmosphere.
Self- and N
2-broadening coefficients of H
2CO have been retrieved in both the 3.5 and 5.7-μm spectral regions. These coefficients have been measured in FT spectra for transitions with various
J ...(from 0 to 25) and
K values (from 0 to 10), showing a clear dependence with both rotational quantum numbers
J and
K. First, an empirical model is presented to reproduce the rotational dependence of the measured self- and N
2-broadening coefficients. Then, calculations of N
2-broadening of H
2CO were made for some for 3296
ν
2 transitions using the semi-classical Robert–Bonamy formalism. These calculations have been done for various temperatures in order to obtain the temperature dependence of the line widths. Finally, self- and N
2-broadening coefficients, as well as temperature dependence of the N
2-widths has been generated to complete the whole HITRAN 2008 version of formaldehyde (available as supplementary materials).
To determine high-resolution rovibrational levels of the inversion vibrational (v
2
= 1) state of the
15
NHD
2
molecule, the Fourier spectrum in the range from 650 to 1150 cm
–1
is studied. The data ...obtained are used to determine the parameters of the effective Hamiltonian of the examined molecule.
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