André Fayt

The HITRAN molecular spectroscopic database: edition of 2000 including updates through 2001

This paper describes the status circa 2001, of the HITRAN compilation that comprises the public edition available through 2001. The HITRAN compilation consists of several components useful for radiative transfer calculation codes: high-resolution spectroscopic parameters of molecules in the gas phase, absorption cross-sections for molecules with very dense spectral features, aerosol refractive indices, ultraviolet line-by-line parameters and absorption cross-sections, and associated database management software. The line-by-line portion of the database contains spectroscopic parameters for 38 molecules and their isotopologues and isotopomers suitable for calculating atmospheric transmission and radiance properties. Many more molecular species are presented in the infrared cross-section data than in the previous edition, especially the chlorofluorocarbons and their replacement gases. There is now sufficient representation so that quasi-quantitative simulations can be obtained with the standard radiance codes. In addition to the description and justification of new or modified data that have been incorporated since the last edition of HITRAN (1996), future modifications are indicated for cases considered to have a significant impact on remote-sensing experiments

The 1997 spectroscopic GEISA databank

The current version GEISA-97 of the computer-accessible database system GEISA (Gestion et Etude des Informations Spectroscopiques Atmospheriques: Management and Study of Atmospheric Spectroscopic Information) is described. This catalogue contains 1,346,266 entries. These are spectroscopic parameters required to describe adequately the individual spectral lines belonging to 42 molecules (96 isotopic species) and located between 0 and 22,656 cm-1. The featured molecules are of interest in studies of the terrestrial as well as the other planetary atmospheres, especially those of the Giant Planets. GEISA-97 contains also a catalog of absorption cross-sections of molecules such as chlorofluorocarbons which exhibit unresolvable spectra. The modifications and improvements made to the earlier edition (GEISA-92) and the data management software are described. GEISA-97 and the associated management software are accessible from the ARA/LMD (Laboratoire de Meteorologie Dynamique du CNRS, France) web site: http://ara01.polytechnique.fr/registration.

High resolution wavenumber standards for the infrared (Technical Report)

The calibration of high resolution infrared spectra is generally more precise than accurate. This is the case even when they are recorded with Fourier transform interferometers. The present document aims at improving the accuracy of wavenumber measurements in the infrared by recommending a selection of spectral lines as wavenumber standards for absolute calibration in the range from about 4 to about 7000 cm(-1). The uncertainties of these wavenumber standards range from 4+/-1x10(-3) to +/-1x10(-6) cm(-1). Sources of frequency standards, on which the wavenumber determinations are based, are also given.

Global rovibrational analysis of carbonyl sulfide

Abstract A global analysis has been applied simultaneously on all data available for the rovibrational energies of carbonyl sulfide 16 O 12 C 32 S in the electronic ground state; data from all kinds of techniques: μW, RF, IR, laser, MBER, Stark, and IR-MWDR have been considered. All off-diagonal terms in the Hamiltonian (anharmonic, l -type, Stark, and polarizability terms) were taken into account in a one-step diagonalization procedure. A statistical agreement is obtained with all data and a set of 66 zero field molecular parameters have been determined (Stark parameters are published in another paper in this journal). Effective level constants and their uncertainties have been calculated up to the eighth order in J ( J + 1) for vibrational levels up to 4950 cm −1 .

CO2 laser saturation Stark spectra and global rovibrational analysis of the main isotopic species of carbonyl sulfide (OC34S, O13CS, and 18OCS)

Abstract Stark spectra of OC 34 S, O 13 CS, and 18 OCS have been recorded with an intracavity CO 2 laser spectrometer. The observed transitions are the 2 ν 2 band and the associated hot bands from ν 2 1 , ν 1 , 2 ν 2 0 , 2 ν 2 2 , ν 1 + ν 2 1 , 3 ν 2 1 , and 3 ν 2 3 . One line has also been observed in the 00 0 1 ← 02 0 0 band of OC 34 S. For each isotopic species of OCS, a global weighted least-squares analysis has been applied simultaneously on all available zero-field and Stark data, yielding coherent sets of rovibrational and electrical molecular parameters. From the equilibrium rotational constants we have deduced an improved equilibrium structure for the OCS molecule.

High resolution infra-red studies of HCCCN and DCCCN

A total of 15 bands of HCCCN and 10 bands of DCCCN, occurring in the region 1800–6500 cm-1, have been recorded at resolutions of between 0·025 and 0·050 cm-1. Sufficient fundamental, overtone, combination and hot bands have been analysed to enable accurate band origins to be determined for v 1, v 2, v 3, v 5, v 6 and v 7 of both isotopic species and to enable estimates of the band origins of v 4 of both isotopic species to be made. The rotational structure of 37 bands has been analysed to yield accurate values of vi 0, (B′-B″) and in some cases, (D′-D″).

Extension to third-order Coriolis terms of the analysis of ν10, ν7, and ν4 levels of ethylene on the basis of Fourier transform and diode laser spectra

Abstract The ν 7 , ν 10 , and ν 4 levels of ethylene have been studied based on waveguide laser, Fourier transform, and diode laser spectra in the range from 798 to 1091 cm −1 . The absolute calibration of these spectra is better than 0.0002 cm −1 . To deal with so many and so accurate experimental data, we have developed in our analysis programs the Watson Hamiltonian up to the sextic centrifugal distortion coefficients and the interaction Hamiltonian up to the third-order Coriolis resonance terms. The molecular parameters of the vibrational ground state have been significantly improved on the basis of more than 4000 GSCD. In the analysis of ν 7 , ν 10 , and ν 4 levels, we had to introduce the ν 12 level, which contributes to the indirect coupling of ν 7 and ν 4 through strong Coriolis interactions. We obtain a statistical agreement with all experimental data with an estimated standard deviation equal to 0.84. The intrinsic intensity of the ν 10 band has been determined to be 16 500 ± 2500 times lower than the intensity of the ν 7 band.

The absorption of ethylene in the 10- mu m region

The nu /sub 7/, nu /sub 10/, and nu /sub 4/ interacting band system has been studied from three complementary sources: classical, diode laser, and waveguide laser spectra. In addition to the two first-order Coriolis interaction terms associated with zeta /sub 7,10//sup a/ and zeta /sub 4,10//sup b /, we were obliged to introduce the corresponding second-order terms to obtain a statistical agreement between calculated and experimental data. High-quality vibrational and rotational data are presented for the two infrared active fundamentals, nu /sub 7/ and nu /sub 10/, and the rotational constants for the inactive nu /sub 4/ fundamental are determined for the first time. The authors present the list of all the infrared transitions starting from the vibrational ground state of ethylene and being in quasi coincidence with CO/sub 2/ or N/sub 2/O laser lines.

Vibration-rotation pattern in acetylene. II. Introduction of Coriolis coupling in the global model and analysis of emission spectra of hot acetylene around 3 mu m

A high temperature source has been developed and coupled to a high resolution Fourier transform spectrometer to record emission spectra of acetylene around 3 mum up to 1455 K under Doppler limited resolution (0.015 cm(-1)). The nu(3)-ground state (GS) and nu(2)+nu(4)+nu(5) (Sigma(u) (+) and Delta(u))-GS bands and 76 related hot bands, counting e and f parities separately, are assigned using semiautomatic methods based on a global model to reproduce all related vibration-rotation states. Significantly higher J-values than previously reported are observed for 40 known substates while 37 new e or f vibrational substates, up to about 6000 cm(-1), are identified and characterized by vibration-rotation parameters. The 3 811 new or improved data resulting from the analysis are merged into the database presented by Robert et al. [Mol. Phys. 106, 2581 (2008)], now including 15 562 lines accessing vibrational states up to 8600 cm(-1). A global model, updated as compared to the one in the previous paper, allows all lines in the database to be simultaneously fitted, successfully. The updates are discussed taking into account, in particular, the systematic inclusion of Coriolis interaction.

Acetylene, 12C2H2: new CRDS data and global vibration-rotation analysis up to 8600 cm-1

The absorption spectrum of 12C2H2 has been recorded using cavity ringdown spectroscopy and analyzed in the ranges 6000 − 6356 cm−1 and 6667−7015 cm−1. Fourteen new bands have been identified and additional J-lines were assigned in 10 already known bands. These new data, together with the published vibration–rotation absorption lines of 12C2H2 accessing vibrational states up to 8600 cm−1 have been gathered in a database. The resulting set includes 12137 transitions involving 186 different k = l 4 + l 5 sub-states, with l i the angular momentum quantum number associated to the i degenerate bending vibration. These lines have been fitted simultaneously to spectroscopic parameters through J-dependent Hamiltonian matrices exploiting the vibrational polyad or cluster block-diagonalization, in terms of the pseudo-quantum numbers Nr = 5v 1 + 3v 2 + 5v 3 +v 4 +v 5 and Ns = v 1 + v 2 + v 3, also accounting for k and e/f parities and u/g symmetry. Modes 1 and 2 correspond to the symmetric CH and CC stretchings, mode 3 to the antisymmetric CH stretch, and modes 4 and 5 to the trans- and cis-degenerate bendings, respectively. The fit was successfully achieved, with a dimensionless standard deviation of 0.92, leading to the determination of 266 effective vibration-rotation parameters.