C. Camy-Peyret

THE HITRAN MOLECULAR SPECTROSCOPIC DATABASE AND HAWKS (HITRAN ATMOSPHERIC WORKSTATION): 1996 EDITION

Since its first publication in 1973, the HITRAN molecular spectroscopic database has been recognized as the international standard for providing the necessary fundamental spectroscopic parameters for diverse atmospheric and laboratory transmission and radiance calculations. There have been periodic editions of HITRAN over the past decades as the database has been expanded and improved with respect to the molecular species and spectral range covered, the number of parameters included, and the accuracy of this information. The 1996 edition not only includes the customary line-by-line transition parameters familiar to HITRAN users, but also cross-section data, aerosol indices of refraction, software to filter and manipulate the data, and documentation. This paper describes the data and features that have been added or replaced since the previous edition of HITRAN. We also cite instances of critical data that are forthcoming.

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.

The far infrared spectrum of H2O2. First observation of the staggering of the levels and determination of the cis barrier

High resolution spectra of H2O2, recorded by means of Fourier transform spectroscopy between 30 and 460 cm−1, have been analyzed leading to the determination of the rotational levels of the torsional states (n,τ) for n=0,1,2,3. In order to reproduce these energy levels, Watson type Hamiltonians have been used and it has been possible to observe a staggering of the levels with n=2 and 3 caused by the cis barrier. The torsional band centers have then been fitted using a torsional Hamiltonian of the form {Bγγ,J2γ} +V(γ) with the potential function V(γ) written as V(γ)=V1 cos 2γ+V2 cos 4γ+V3 cos 6γ+V4 cos 8γ where the torsional coordinate 2γ is the dihedral angle defining the relative position of the two O–H bonds. The potential constants in cm−1 are V1=1036.97±23.1 cm−1, V2=657.53±5.2 cm−1, V3=50.89±3.3 cm−1, V4=2.524±0.83 cm−1 which correspond to barrier heights Vtrans =387.07±0.20 cm−1, Vcis =2562.8±60 cm−1, and to a potential minimum located at 2γ=111.9°±0.4° from the cis configuration. It is also shown t...

The High-Resolution Spectrum of Water Vapor between 11 600 and 12 750 cm-1

The absorption spectrum of water vapor has been recorded between 11 600 and 12 750 cm-1 with a Fourier transform spectrometer (Kitt Peak, Az) at a resolution of 0.012 cm-1 and with a path length of 434 m. The line assignment has led to the determination of 506 accurate energy levels of the (310) (211), (112), (013), (230), (131), (032), and (051) vibrational states which belong to the so-called 3nu + delta resonance polyad. The rotational energy levels obtained are on the average in agreement with those reported recently by R. Toth (J. Mol. Spectrosc. 166, 176-183 (1994)) for the strong bands, but there are differences for high J levels or weak bands levels (about 15% of all levels). The experimental rotational energy levels have been fitted using Pade-Borel approximants and a set of 104 vibrational energies and rotational, resonance, and centrifugal distortion constants for the (310), (211), (112), (013), (230), (131), (032), and (051) vibrational states have been determined.

The ν1 and ν3 bands of 16O3: Line positions and intensities

Abstract Using 0.005 cm −1 resolution Fourier transform spectra of samples of ozone, the ν 1 and ν 3 bands of 16 O 3 have been reanalyzed to obtain accurate line positions and an extended set of upper state rotational levels ( J up to 69, K a up to 20). Combined with the available microwave data, these upper state rotational levels were satisfactorily fitted using a Hamiltonian which takes explicitly into account the strong Coriolis interaction affecting the rotational levels of these two interacting states. In addition, 350 relative line intensities were measured from which the rotational expansions of the transition moment operators for the ν 1 and ν 3 states have been deduced. Finally, a complete listing of line positions, intensities, and lower state energies of the ν 1 and ν 3 bands of 16 O 3 has been generated.

The interacting states (030), (110), and (011) of H216O

Abstract A fit of 382 rotational levels of the three vibrational states (030), (110), and (011) of H 2 16 O has been performed using 51 effective constants. The Fermi-type interaction between (030) and (110) and the Coriolis-type interaction between (110) and (011) as well as between (030) and (011) are taken into account. The part of the Hamiltonian which is diagonal in the vibrational quantum numbers is a Watson-type Hamiltonian. Considering the wide spread of J and K a values, the general agreement between experimental and calculated levels is satisfactory. A comparison with the results relative to the states (020), (100), and (001) is given.

Torsion-vibration interaction in H2O2: First high-resolution observation of ν3

Abstract High-resolution Fourier transform spectra recorded between 450 and 1050 cm −1 have been used to obtain an extensive analysis of several vibration-torsion-rotation bands of H 2 O 2 leading to a precise and extended set of torsion-rotation levels in both the ground and the ν 3 vibrational states of this molecule. In particular, the first observation of the ( n , τ ) = (0, 1) and (0, 3) torsional states of the v 3 = 1 vibrational state is reported. The centers of these two torsional bands are 865.939 and 877.934 cm −1 , respectively. In addition to the observation of ν 3 , new results concerning the ( n , τ) torsional states of the ground state up to n = 3 are presented. All the observed levels have been reproduced with the aid of a Hamiltonian which takes into account the torsion-rotation interactions within a given vibrational state, the staggering due to the cis -barrier, and the strong Coriolis-type interaction which couples the levels of the ground state with those of the v 3 = 1 state. Indeed it is impossible to treat the ground state levels without this interaction, which has been considered here for the first time.

Line positions and intensities for the ν1 + ν2 and ν2 + ν3 bands of H218O

Abstract The intensities of about 90 lines of the ν 1 + ν 2 and ν 2 + ν 3 bands of H 2 18 O have been measured using a Fourier transform spectrum of natural water vapor. The constants involved in the rotational expansion of the transformed transition moment operators corresponding to these bands have been determined through a fit of these line intensities. The constants obtained are used to compute the whole spectrum of the ν 1 + ν 2 and ν 2 + ν 3 bands of H 2 18 O providing reliable line positions and intensities. For lines involving perturbed levels a comparison is given with the results obtained for H 2 16 O and it is shown that the results for one isotopic species cannot be transferred directly to another one.

The far infrared spectrum of 14N16O2

High resolution Fourier transform spectra in the 8–200 cm-1 spectral region have been used to analyse the pure rotation spectrum of nitrogen dioxide. In this way, the spin rotation levels of the (000) state were accurately measured for Ka up to 14 and N up to 54. Using a hamiltonian which takes the spin-rotation and the hyperfine operators explicitly into account, it has been possible to derive a complete set of molecular parameters (rotational, spin-rotation and hyperfine constants) for the (000) state of 14N16O2 from these experimental data and from the available microwave measurements. Numerous perturbations due to the hyperfine Fermi contact operator were analysed as well as a local resonance [42 0 42, J = 41·5] ↔ [41 2 40, J = 41·5] due to the electron spin-rotation interaction. Finally, a synthetic spectrum of the (000) ← (000) band of 14N16O2 including all hyperfine transitions has been computed, covering the 0–235 cm-1 spectral region.