Papers by Ludovic Daumont
Fourier Transform Spectroscopy, 2003
Our understanding of the physical and chemical properties of the terrestrial atmosphere relies to... more Our understanding of the physical and chemical properties of the terrestrial atmosphere relies to a large extent on optical remote sensing measurements using various platforms (ground, airborne, satellites). The analysis of the atmospheric spectra recorded and the accuracy ...
Formaldehyde (H_2CO) is an important intermediate compound in the degradation of the volatile org... more Formaldehyde (H_2CO) is an important intermediate compound in the degradation of the volatile organic compounds (VOCs), including methane, in the terrestrial troposphere. Its observation using optical remote sensing in the infrared range relies on the 3.6 and 5.7 mum absorption bands. Band and individual line intensities have been reported in both ranges. With the present work, we aim to also derive infrared line intensities for formaldehyde, however relying on pure rotation line intensities and the known electric dipole moment to determine the particle density. Indeed, because formaldehyde polymerizes or degrades easily, the gas phase may contain polymerization or degradation products. Spectra of H_2CO diluted in 10 hPa of N_2 were therefore simultaneously recorded in the 20-60 Cm-1 and 3.6 mum ranges, respectively using a Bruker IFS125HR Fourier transform spectrometer and a tunable diode laser. see A. Perrin, D. Jacquemart, F. Kwabia Tchana, N. Lacome, J. Quant. Spectrosc. Radiat....
This paper reports the first assignment of rovibrational transitions of the 54 and 2+44 band s... more This paper reports the first assignment of rovibrational transitions of the 54 and 2+44 band systems of 12CH4 in the 6287-6550 cm-1 region which is usually referred to as part of the 1.6 m methane transparency window. The analysis was based on two line lists previously obtained in Grenoble by Cavity Ring Down Spectroscopy at T= 297 K and 79 K completed by three long path Fourier Transform Spectra recorded in Reims (L=1603 m, P= 1-34 mbar). In order to determine the dipole transition moment parameters and quantify the intensity borrowing due to the resonance interactions, we had to include in the fit of the effective Hamiltonian model some lines of the stronger 1+34 and 2+44 bands. For this purpose, intensities of 179 additional lines were retrieved from FTS spectra above 6550 cm-1 though the analysis of these higher bands is not complete. About 1955 experimental line positions and 1462 line intensities were fitted with RMS standard deviations of 0.003 cm-1 and 13.4%, respect...
Proceedings of the 69th International Symposium on Molecular Spectroscopy, 2014
Pure and Applied Chemistry
The report of an IUPAC Task Group, formed in 2011 on "Intensities and line shapes in high-re... more The report of an IUPAC Task Group, formed in 2011 on "Intensities and line shapes in high-resolution spectra of water isotopologues from experiment and theory" (Project No. 2011-022-2-100), on line profiles of isolated high-resolution rotational-vibrational transitions perturbed by neutral gas-phase molecules is presented. The well-documented inadequacies of the Voigt profile (VP), used almost universally by databases and radiative-transfer codes, to represent pressure effects and Doppler broadening in isolated vibrational-rotational and pure rotational transitions of the water molecule have resulted in the development of a variety of alternative line-profile models. These models capture more of the physics of the influence of pressure on line shapes but, in general, at the price of greater complexity. The Task Group recommends that the partially Correlated quadratic-Speed-Dependent Hard-Collision profile should be adopted as the appropriate model for high-resolution spect...
The precise knowledge of the methane absorption in the study of planetary systems, and especially... more The precise knowledge of the methane absorption in the study of planetary systems, and especially of Titan (Saturn's largest satellite whose atmosphere is mainly composed of nitrogen and methane at temperatures ranging between 70 K and 200 K), is of great importance because it gives access to the determination of the physical properties of these objects. The full interpretation of the Titan data returned by the ground-based and space observations has been hindered by the lack of precise knowledge of the methane absorption which dominates Titan's near infrared spectra. We investigate the methane spectra in the closest conditions to existing Titan's spectra. We used the 50 m long cell from Reims university in front of the Home-made Fourier Transform Spectrometer to study the 12CH_4 spectra with 1603 m absorption path length, 1, 7 and 34 hPa pressures and at room temperature. The spectra was recorded in the all range from 3800 to 8100 Cm-1. The up-to-date measurements an...
Pure and Applied Chemistry, 2000
Water Transitions from Experiment and Theory" (Project No. 2004-035-1-100) are presented. Energy ... more Water Transitions from Experiment and Theory" (Project No. 2004-035-1-100) are presented. Energy levels and recommended labels involving exact and approximate quantum numbers for the main isotopologues of water in the gas phase, H 2 16 O, H 2 18 O, H 2 17 O, HD 16 O, HD 18 O, HD 17 O, D 2 16 O, D 2 18 O and D 2 17 O, are determined from measured transition frequencies and validated using first principles nuclear motion computations and the MARVEL (Measured Active Rotational-Vibrational Energy Levels) approach. The extensive data including lines and levels are required
Journal of Quantitative Spectroscopy and Radiative Transfer, 2011
ABSTRACT This paper reports the first assignment of rovibrational transitions of the 5ν4 and ν2+4... more ABSTRACT This paper reports the first assignment of rovibrational transitions of the 5ν4 and ν2+4ν4 band systems of 12CH4 in the 6287–6550 cm−1 region, which is usually referred to as part of the 1.58 μm methane transparency window. The analysis was based on two line lists previously obtained in Grenoble by cavity ring down spectroscopy at T=297 and 79 K completed by three long-path Fourier transform spectra recorded in Reims (at 290 K, L=1603 m, P=1–34 mbar). In order to determine the dipole transition moment parameters and quantify the intensity borrowing due to the resonance interactions, we had to include in the fit of the effective Hamiltonian model some lines of the stronger ν1+3ν4 and ν2+4ν4 bands. For this purpose, intensities of 179 additional lines were retrieved from FTS spectra above 6550 cm−1 though the analysis of these higher bands is not complete. About 1955 experimental line positions and 1462 line intensities were fitted with RMS standard deviations of 0.003 cm−1 and 13.1%, respectively. A line list of 8029 calculated and observed transitions which are considered as dominant was constructed for 12CH4 in the 6287–6550 cm−1 region. This is the first high-resolution analysis and modelling of 5-quanta band systems of 12CH4.
Journal of Quantitative Spectroscopy and Radiative Transfer, 2010
Absorption spectra of HDO/D 2 O mixtures recorded in the 5600-8800 cm À 1 region with a total pre... more Absorption spectra of HDO/D 2 O mixtures recorded in the 5600-8800 cm À 1 region with a total pressure of water from 13 up to 18 hPa and an absorption path length of 600 m have been analyzed in order to obtain new spectroscopic data for HD O and D 2 18 O. In spite of the low natural 18 O concentration (about 2 Â 10 À 3 with respect to the 16 O one), about 1100 transitions belonging to HD 18 O and more than 280 transitions belonging to D 2 18 O have been assigned. Most of the D 2 18 O transitions belong to the n 1 +n 2 + n 3 and 2n 1 + n 3 bands. Sets of energy levels for seven vibrational states of D 2 18 O and four states of HD 18 O are reported for the first time. The comparison of the experimental data with the calculated values based on Partridge-Schwenke global variational calculations is discussed.
Journal of Quantitative Spectroscopy and Radiative Transfer, 2005
The content of the current version, GEISA/IASI-03, of the computer-accessible spectroscopic datab... more The content of the current version, GEISA/IASI-03, of the computer-accessible spectroscopic database, GEISA/IASI, is described. This ''system'' or database is comprised of three independent spectroscopic archives, which are (a) a database of individual spectral line parameters on 14 molecules, H 2 O; CO 2 ; O 3 ; N 2 O; CO, CH 4 ; O 2 ; NO, SO 2 ; NO 2 ; HNO 3 ; OCS, C 2 H 2 ; N 2 ; and the related 51 isotopomers and isotopologues, representing 702,550 entries, in the spectral range 599-3001 cm À1 ; (b) a database of spectral absorption cross-sections (6,572,329 entries related to six molecules, CFC-11, CFC-12, CFC-14, HCFC-22, N 2 O 5 ; CCl 4 ), and a catalogue of microphysical and optical properties (mainly, the refractive indices) of atmospheric aerosols. The modifications and improvements, which have been implemented since the earlier editions of this database, in terms of content and management, have been explained in detail. GEISA/IASI has been created with the specific purpose of assessing the capability of measurement by the IASI instrument within the designated goals of ISSWG in the frame of the CNES/EUMETSAT European Polar System preparation.
Journal of Quantitative Spectroscopy and Radiative Transfer, 2014
and sharing with colleagues.
Journal of Quantitative Spectroscopy and Radiative Transfer, 2002
New line intensity measurements in the 10 m region of 14 N 2 16 O have been performed using FTS i... more New line intensity measurements in the 10 m region of 14 N 2 16 O have been performed using FTS in Paris and Reims. About 150 lines in hot bands, including those of the forbidden 0330 -0110 band, have been measured for the ÿrst time. The new observations together with those available in this region have been used in the ÿt of e ective dipole moment parameters. A dimensionless weighted standard deviation of 1.28 and a RMS deviation of 4.2% have been obtained. Some disagreements with previous measurements and with the HITRAN and GEISA databases have been pointed out for the 0001-1000 and 0220 -0000 bands. ?
Journal of Quantitative Spectroscopy and Radiative Transfer, 2009
All available transitions from microwave to visible region (0.2-12 105 cm À1 ) of the HD 18 O mol... more All available transitions from microwave to visible region (0.2-12 105 cm À1 ) of the HD 18 O molecule were collected and tested using the RITZ computer code. Literature data were completed by transitions assigned to HD 18 O in long path Fourier transform absorption spectra of the H 2 O, HDO and D 2 O gas mixtures with natural abundance of oxygen-18. In addition about 40 unassigned lines between 4200 and 6600 cm À1 of our previous water study associated with the HD 18 O molecule have been found and assigned. The new long path absorption spectra of the HDO and D 2 O mixtures allow us to observe about 1000 transitions of HD 18 O in the 6125-10 720 cm À1 spectral region. These data have been critically analyzed and used to obtain the most complete and precise set of the experimental energy levels of this molecule.
Journal of Quantitative Spectroscopy and Radiative Transfer, 2008
... a Laboratoire de Météorologie Dynamique/Institut Pierre Simon Laplace, Ecole Polytechnique, R... more ... a Laboratoire de Météorologie Dynamique/Institut Pierre Simon Laplace, Ecole Polytechnique, Route Départementale 36, 91128 Palaiseau, France. ... d Institut Pierre Simon Laplace, UniversitéPierre et Marie Curie, 4 Place Jussieu, 75252 Paris, France. ...
Journal of Quantitative Spectroscopy and Radiative Transfer, 2007
Journal of Quantitative Spectroscopy and Radiative Transfer, 2007
The absorption spectrum of N 2 O, at room temperature, was recorded in the 540011 000 cm 1 regi... more The absorption spectrum of N 2 O, at room temperature, was recorded in the 540011 000 cm 1 region at resolutions ranging from 0.008 cm 1 near 5400 to 0.023 cm 1 near 11 000 cm 1 using a Bruker IFS120HR Fourier transform spectrometer. Sample ...
Journal of Quantitative Spectroscopy and Radiative Transfer, 2004
The rovibrational line intensities of the N 2 O molecule in its ground electronic state have been... more The rovibrational line intensities of the N 2 O molecule in its ground electronic state have been used to determine its dipole moment derivatives using a ÿtting procedure. The wavefunctions calculation have been made using a Discrete Variable Representation method in Radau coordinates and an available potential energy surface. The resulting dipole moment derivatives are compared to previous ones obtained using normal coordinates approach. ?
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Papers by Ludovic Daumont