Olga V. Naumenko

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 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.

Recommended isolated-line profile for representing high-resolution spectroscopic transitions (IUPAC Technical Report)

Abstract 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 (pCqSD-HCP) should be adopted as the appropriate model for high-resolution spectroscopy. For simplicity this should be called the Hartmann–Tran profile (HTP). The HTP is sophisticated enough to capture the various collisional contributions to the isolated line shape, can be computed in a straightforward and rapid manner, and reduces to simpler profiles, including the Voigt profile, under certain simplifying assumptions.

A database of water transitions from experiment and theory (IUPAC technical report)

Abstract The report and results of an IUPAC Task Group (TG) formed in 2004 on “A Database of 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, H216O, H218O, H217O, HD16O, HD18O, HD17O, D216O, D218O, and D217O, are determined from measured transition frequencies. The transition frequencies and energy levels are 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 for analysis and synthesis of spectra, thermochemical applications, the construction of theoretical models, and the removal of spectral contamination by ubiquitous water lines. These datasets can also be used to assess where measurements are lacking for each isotopologue and to provide accurate frequencies for many yet-to-be measured transitions. The lack of high-quality frequency calibration standards in the near infrared is identified as an issue that has hindered the determination of high-accuracy energy levels at higher frequencies. The generation of spectra using the MARVEL energy levels combined with transition intensities computed using high accuracy ab initio dipole moment surfaces are discussed. A recommendation of the TG is for further work to identify a single, suitable model to represent pressure- (and temperature-) dependent line profiles more accurately than Voigt profiles.

The absorption spectrum of water near 750 nm by CW-CRDS: contribution to the search of water dimer absorption

The absorption spectrum of natural water vapour around 750 nm has been recorded with a typical sensitivity of 3 x 10(-10) cm(-1) using a cw cavity ring down spectroscopy set up based on a Ti:sapphire laser. The 13 312.4-13 377.7 cm(-1) spectral interval was chosen as it corresponds to the region where water dimer absorption was recently measured (K. Pfeisticker et al., Science, 2003, 300, 2078-2080). The line parameters (wavenumber and intensity) of a total of 286 lines of water vapor were measured by a one by one fit of the lines to a Voigt profile. For the main water isotopologue, 276 lines were measured with line intensities as weak as 5 x 10(-29) cm molecule(-1)i.e. about 50 times smaller than the weakest H(2)16O line intensities included in the 2004 edition of the HITRAN database. On the basis of the predictions of Schwenke and Partridge, all but 16 lines could be assigned to different isotopologues of water (H(2)16O, H(2)18O, and HD16O) present in natural abundance in the sample. A total of 272 energy levels of H(2)16O were determined and rovibrationally assigned to 18 upper vibrational states. Half of them had not been reported previously. The importance of the additional absorbance resulting from the observation of many new weak lines is discussed in relation to the detection of water dimer absorption and compared to the absorbance predicted by Schwenke and Partridge. The quality of the line parameters of water monomer is shown to be of crucial importance to identify the absorbance of the water dimer in the considered region.

The laser spectroscopy of highly excited vibrational states of HD16O

Abstract The absorption spectra of HD 16 O were recorded using a F 2 + :LiF color center intracavity laser spectrometer in the 0.9-μm region and an optoacoustic dye laser spectrometer in the 0.59-μm spectral region. Energy levels and rotational and centrifugal distortion constants of the (003) and (005) states were determined. Improved sets of vibrational and vibration-rotation constants have been obtained by fitting all available data for the energy levels of HDO.

LOCAL MODE AXIS TILTING IN H2S

A physically intuitive non-resonant local mode axis tilting model for the interpretation of higher overtone bands of XH2 species is outlined and illustrated by reference to the near2 infrared of spectrum H2S. Quantitative connections with the conventional normal mode resonance coupled picture are derived and local mode based expressions for the vibrational–rotational wavefunctions are given. Constants are reported for the (311)–(212) and (302)–(203) bands at 11 008cm-1 and 12 149cm -1, respectively.

Rovibrational analysis of the absorption spectrum of HDO between 10 110 and 12 215 cm−1

The weak absorption spectrum of monodeuterated water has been investigated between 10 110 and 12 215 cm−1 by high resolution Fourier transform absorption spectroscopy with a 105 m absorption pathlength. The spectrum is dominated by the 4ν1, 3ν3, and ν2 + 3ν3 bands at 10 378.95, 10 631.68 and 11 969.76 cm−1, respectively. The rovibrational assignment was performed on the basis of the ab initio calculations of Schwenke and Partridge and by using the effective Hamiltonian approach. 502 energy levels belonging to a total of 13 vibrational states were determined. The rotational structure of the (003) state is mostly isolated and could be fitted with an rms of 0.006 cm−1, slightly larger than the experimental uncertainty. Most of the other levels are connected via a complex interaction scheme involving dark states which prevented a satisfactory modeling. The analysis of the rotational structure of the (013), (400) and (112) states is investigated for the first time, while the existing information for the (003) state is considerably enlarged and improved. Transitions reaching the nine other (dark) states, including the highly excited bending states, (051), (061) and (080), were detected in the spectrum as a result of intensity borrowing due to resonance interactions with bright states.

High-resolution spectroscopy of the triple-substituted isotopologue of water molecule D_{\bf 2}^{\bf 18}O: the first triad

The high-resolution Fourier-transform absorption spectrum of the triple-substituted isotopologue of the water molecule, D O is measured in the 1700–9000 cm−1 region. The transitions of the ν1, 2ν2 and ν3 bands are assigned with the help of the high accuracy variational calculations based on an empirical mass-dependent Partridge–Schwenke potential energy surface. The fittings based on an effective Hamiltonian model are also utilized to confirm the assignments. A set of 816 precise ro-vibrational energy levels for the first triad of interacting vibrational states: (0 0 1), (1 0 0) and (0 2 0) is retrieved. With the upper state combination differences, the ground state energy levels are extended to J max = 23 and . These levels can be used to check the quality of the recently available high accuracy ab initio potential energy surface of the water molecule.

Information system for molecular spectroscopy. 5. Ro-vibrational transitions and energy levels of the hydrogen sulfide molecule

This work considers the verification, systematization, and publication in the W@DIS information system of all published data acquired at the moment by various authors from the analysis of high resolution, ro-vibrational spectra of hydrogen sulfide and its isotopologues. The system interface allows prompt and efficient search for any required information by specified criteria. The W@DIS information system, in its present state, contains the most complete and reliable information on ro-vibrational transitions and energy levels of the hydrogen sulfide molecule as compared with other databases. The data systematized in this work may serve as a source of information for problems of theoretical spectroscopy and chemistry, atmospheric problems, and other applications.