Laurence S. Rothman

The hitran molecular database : editions of 1991 and 1992

Abstract We describe in this paper the modifications, improvements, and enhancements to the HITRAN molecular absorption database that have occurred in the two editions of 1991 and 1992. The current database includes line parameters for 31 species and their isotopomers that are significant for terrestrial atmospheric studies. This line-by-line portion of HITRAN presently contains about 709,000 transitions between 0 and 23,000 cm-1 and contains three molecules not present in earlier versions: COF2, SF6, and H2S. The HITRAN compilation has substantially more information on chlorofluorocarbons and other molecular species that exhibit dense spectra which are not amenable to line-by-line representation. The user access of the database has been advanced, and new media forms are now available for use on personal computers.

The HITRAN database - 1986 edition

A description and summary of the latest edition of the AFGL HITRAN molecular absorption parameters database are presented. This new database combines the information for the seven principal atmospheric absorbers and twenty-one additional molecular species previously contained on the AFGL atmospheric absorption line parameter compilation and on the trace gas compilation. In addition to updating the parameters on earlier editions of the compilation, new parameters have been added to this edition such as the self-broadened halfwidth, the temperature dependence of the air-broadened halfwidth, and the transition probability. The database contains 348043 entries between 0 and 17,900 cm(-1). A FORTRAN program is now furnished to allow rapid access to the molecular transitions and for the creation of customized output. A separate file of molecular cross sections of eleven heavy molecular species, applicable for qualitative simulation of transmission and emission in the atmosphere, has also been provided.

AFGL atmospheric absorption line parameters compilation - 1982 edition

The latest edition of the AFGL atmospheric absorption line parameters compilation for the seven most active infrared terrestrial absorbers is described. Major modifications to the atlas for this edition include updating of water-vapor parameters from 0 to 4300 cm(-1), improvements to line positions for carbon dioxide, substantial modifications to the ozone bands in the middle to far infrared, and improvements to the 7- and 2.3-microm bands of methane. The atlas now contains approximately 181,000 rotation and vibration-rotation transitions between 0 and 17,900 cm(-1). The sources of the absorption parameters are summarized.

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.

Infrared energy levels and intensities of carbon dioxide—II

Abstract Energy levels and rotational constants are provided for all carbon dioxide infrared absorption transitions of significance for terrestrial atmospheric transmission. Constants have been recalculated using new FTS measurements in the 4.3 μm region at elevated temperature, new FTS measurements in the 15, 5, and 2 μm regions, precise laser measurements around 10 μm, and high resolution grating spectrometer measurements of isotopically enriched samples. Band centers, band strengths, and coriolis coupling constants are given for some 560 bands.

AFGL trace gas compilation: 1982 version

The new edition of the AFGL trace gas compilation is described. The latest version provides the necessary parameters for the computation of absorption or emission spectra of major bands of twenty-one gases in the region from 0 to 10,000 cm−1. Emphasis on this edition has been on the addition of numerous millimeter and submillimeter transitions, the inclusion of bands of significance in upper atmospheric processes, and strong IR bands of trace constituents likely to be used for remote detection. The sources for the additions and modifications of the absorption parameters are summarized.

Infrared energy levels and intensities of carbon dioxide. Part 3

Updated tables of vibrational energy levels, molecular constants, band origins, and intensities for carbon dioxide in the infrared region of the spectrum are presented. These tables are references for the AFGL Atmospheric Absorption Line Parameters Compilation.

Total internal partition sums for molecules in the terrestrial atmosphere

Total internal partition sums (TIPS) are calculated for most of the infrared absorbing molecules in the terrestrial atmosphere. The list includes the principal isotopic species and many of the lesser abundant isotopomers. The calculations are made for temperatures from 70 to 3005 K. The temperature range is divided into three regions and the resulting TIPS are fit to a thirdorder polynomial expression for later rapid recall of the total partition sum, Q(T). The method of calculation of Q(T) for each isotopomer, convergence of the partition sum in each temperature range, the quality of the fit of the data, and comparisons with other work are discussed. q 2000 Elsevier Science B.V. All rights reserved.

Direct numerical diagonalization : wave of the future

Abstract The direct numerical diagonalization (DND) technique has been developed for use in calculations of atmospheric opacity due to molecular absorption under conditions which cannot be duplicated in an Earth-based laboratory. DND is an adaptation of the well-known variational method for solving the quantum mechanical equations of the rovibrational molecular Hamiltonian. The method has made possible the analysis and assignment of CO 2 lines for bands that have not been observed before due to the density of the neighboring spectra. Comparison of DND predicted line intensities for the 10 μm laser bands with recent measurements, obtained from two separate laboratories, indicate that the predicted line intensities are basically as good as the best measurements available today. Venus atmosphere simulations, using the most recent DND results, show excellent agreement with new Venus spectra in the 1 μm region, although no Earth-based laboratory is probably capable of measuring the line parameters used in the simulation. Recently, the rectilinear (normal) coordinate formulation of the method used for the CO 2 calculations has been extended to curvilinear (valence) coordinates, and the method was then applied to the calculation of the opacity of H 2 O. We plan to solve the rovibrational problem for N 2 O, SO 2 , O 3 and NO 2 , as well as to extend the technique to small molecules having more than three atoms, such as NH 3 and CH 4 .

GLOBAL FITTING OF 12C16O2 VIBRATIONAL–ROTATIONAL LINE POSITIONS USING THE EFFECTIVE HAMILTONIAN APPROACH

About 13 000 experimental lines of the principal isotopic species of CO2 selected from the literature have been used to derive about 100 parameters of a reduced effective Hamiltonian built up to sixth order in the Amat–Nielsen ordering scheme. This Hamiltonian has been obtained from an effective Hamiltonian describing all vibrational–rotational energy levels in the ground electronic state and containing in explicit form all resonance interaction terms due to the approximate relations between harmonic frequencies ω1≈2ω2andω3≈ω1+ω2. An RMS deviation of 0.001 cm-1 has been achieved in the fitting. In order to test its predictive capabilities, the model has been used to calculate the line positions of six bands: 05511←05501, 1005(1, 2)←1004(1, 2), 1006(1, 2)←1005(1, 2), and 20033←00001, which are compared with experimental lines not included in the data set. The results are discussed and compared with the predictions of the Direct Numerical Diagonalization technique.