Investigation of the shape of the R(0) absorption line in ν3, N2O recorded from an axisymmetric supersonic free jet expansion

The hydrodynamic structure of an axisymmetric supersonic expansion can be regarded as a series of concentric divergent cones, with decreasing particle densities as the cone angle increases. Different groups of molecules therefore contribute to high-resolution absorption line shapes when optically probing the expansion in a direction perpendicular to the jet axis. These groups are distinguished by the cone angle, inducing a specific Doppler shift, and by the particle density, contributing a specific weight to the absorption intensity. As a result different broader line profiles are observed compared to room temperature spectra. This effect is investigated here selecting as the working example the R(0), ν3 absorption line in N2O recorded using a Fourier transform interferometer. Independent impact pressure and quadrupole mass spectrometric measurements are performed leading to two complementary maps of the expansion, allowing the recorded absorption line shape to be quantitatively modeled. © 2006 Elsevier Ltd. All rights reserved.

Water vapor line parameters in the 13 000-9250 cm-1 region.

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SO2 depletion in tropospheric volcanic plumes

Ground based remote sensing techniques are used to measure volcanic SO2 fluxes in efforts to characterise volcanic activity. As these measurements are made several km from source there is the potential for in-plume chemical transformation of SO2 to sulphate aerosol (conversion rates are dependent on meteorological conditions), complicating interpretation of observed SO2 flux trends. In contrast to anthropogenic plumes, SO2 lifetimes are poorly constrained for tropospheric volcanic plumes, where the few previous loss rate estimates vary widely (from ≪1 to >99% per hour .We report experiments conducted on the boundary layer plume of Masaya volcano, Nicaragua during the dry season. We found that SO2 fluxes showed negligible variation with plume age or diurnal variations in temperature, relative humidity and insolation, providing confirmation that remote SO2 flux measurements (typically of ≈500-2000 s old plumes) are reliable proxies for source emissions for ash free tropospheric plumes not emitted into cloud or fog. Copyright 2004 by the American Geophysical Union.

Photophysics of bifunctional Ru(II) complexes bearing an aminoquinoline organic unit. Potential new photoprobes and photoreagents of DNA

[Ru(BPY)2POQ-Nmet]2+ and [Ru(TAP)2POQ-Nmet]2+ (1 and 3) are bifunctional complexes composed of a metallic unit linked by a flexible chain to an organic unit. They have been prepared as photoprobes or photoreagents of DNA. In this work, the spectroscopic properties of these bifunctional complexes in the absence of DNA are compared with those of the monofunctional analogues [Ru(BPY)2Phen]2+, [Ru-(BPY)2acPhen]2+, [Ru(TAP)2Phen]2+, and [Ru(TAP)2acPhen]2+ (2 and 4). The electrospray mass spectrometry and absorption data show that the quinoline moiety exists in the protonated and nonprotonated form. Although the bifunctional complex containing 2,2′-bipyridine (BPY) ligands exhibits photophysical properties similar to those of the monofunctional compounds, the bifunctional complex with 1,4,5,8-tetraazaphenanthrene (TAP) ligands behaves quite differently. It has weaker relative emission quantum yields and shorter luminescence lifetimes than the monofunctional TAP analogue when the quinoline unit is nonprotonated. This indicates an efficient intramolecular quenching of the 3MLCT (metal to ligand charge transfer) excited state of the TAP metallic moiety. When the organic unit is protonated, there is no internal quenching. In organic solvent, the nonquenched excited metallic unit (bearing a protonated quinoline) and the quenched one (bearing a nonprotonated organic unit) are in slow equilibrium as compared to the lifetime of the two emitters. In aqueous solution this equilibrium is faster and is catalysed by the presence of phosphate buffer. Flash photolysis experiments suggest that the intramolecular quenching process originates from a photoinduced electron transfer from the nonprotonated quinoline to the excited Ru(TAP)2 2+ moiety.

Emission spectroscopy from optically thick laboratory acetylene samples at high temperature

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The HITRAN 2008 molecular spectroscopic database

This paper describes the status of the 2008 edition of the HITRAN molecular spectroscopic database. The new edition is the first official public release since the 2004 edition, although a number of crucial updates had been made available online since 2004. The HITRAN compilation consists of several components that serve as input for radiative-transfer calculation codes: individual line parameters for the microwave through visible spectra of molecules in the gas phase; absorption cross-sections for molecules having dense spectral features, i.e. spectra in which the individual lines are not resolved; individual line parameters and absorption cross-sections for bands in the ultraviolet; refractive indices of aerosols, tables and files of general properties associated with the database; and database management software. The line-by-line portion of the database contains spectroscopic parameters for 42 molecules including many of their isotopologues. © 2009 Elsevier Ltd.

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. © 2003 Elsevier Ltd. All rights reserved.

The HITRAN 2004 molecular spectroscopic database

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