39 research outputs found

    ExoMol molecular line lists - XVI: The rotation-vibration spectrum of hot H2_2S

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    This work presents the AYT2 line list: a comprehensive list of 114 million 1^{1}H2_232^{32}S vibration-rotation transitions computed using an empirically-adjusted potential energy surface and an {\it ab initio} dipole moment surface. The line list gives complete coverage up to 11000 \cm\ (wavelengths longer than 0.91 ÎĽ\mum) for temperatures up to 2000 K. Room temperature spectra can be simulated up to 20000 \cm\ (0.5 ÎĽ\mum) but the predictions at visible wavelengths are less reliable. AYT2 is made available in electronic form as supplementary data to this article and at \url{www.exomol.com}.Comment: 12 pages, 10 figures, 10 table

    Recommended Isolated-Line Profile for Representing High-Resolution Spectroscopic Transitions (IUPAC Technical Report)

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    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 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. © 2014 IUPAC & De Gruyte

    IUPAC Critical Evaluation of the Rotational-Vibrational Spectra of Water Vapor, Part III: Energy Levels and Transition Wavenumbers for H216O

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    This is the third of a series of articles reporting critically evaluated rotational-vibrational line positions, transition intensities, and energy levels, with associated critically reviewed labels and uncertainties, for all the main isotopologues of water. This paper presents experimental line positions, experimental-quality energy levels, and validated labels for rotational-vibrational transitions of the most abundant isotopologue of water, H216O. The latest version of the MARVEL (Measured Active Rotational-Vibrational Energy Levels) line-inversion procedure is used to determine the rovibrational energy levels of the electronic ground state of H216O from experimentally measured lines, together with their self-consistent uncertainties, for the spectral region up to the first dissociation limit. The spectroscopic network of H216O contains two components, an ortho (o) and a para (p) one. For o-H216O and p-H216O, experimentally measured, assigned, and labeled transitions were analyzed from more than 100 sources. The measured lines come from one-photon spectra recorded at room temperature in absorption, from hot samples with temperatures up to 3000K recorded in emission, and from multiresonance excitation spectra which sample levels up to dissociation. The total number of transitions considered is 184667 of which 182156 are validated: 68027 between para states and 114129 ortho ones. These transitions give rise to 18486 validated energy levels, of which 10446 and 8040 belong to o-H216O and p-H216O, respectively. The energy levels, including their labeling with approximate normal-mode and rigid-rotor quantum numbers, have been checked against ones determined from accurate variational nuclear motion computations employing exact kinetic energy operators as well as against previous compilations of energy levels. The extensive list of MARVEL lines and levels obtained are deposited in the supplementary data of this paper, as well as in a distributed information system applied to water, W@DIS, where they can easily be retrieved

    IUPAC Critical Evaluation of the Rotational-Vibrational Spectra of Water Vapor, Part III: Energy Levels and Transition Wavenumbers for H216O

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    This is the third of a series of articles reporting critically evaluated rotational-vibrational line positions, transition intensities, and energy levels, with associated critically reviewed labels and uncertainties, for all the main isotopologues of water. This paper presents experimental line positions, experimental-quality energy levels, and validated labels for rotational-vibrational transitions of the most abundant isotopologue of water, H216O. The latest version of the MARVEL (Measured Active Rotational-Vibrational Energy Levels) line-inversion procedure is used to determine the rovibrational energy levels of the electronic ground state of H216O from experimentally measured lines, together with their self-consistent uncertainties, for the spectral region up to the first dissociation limit. The spectroscopic network of H216O contains two components, an ortho (o) and a para (p) one. For o-H216O and p-H216O, experimentally measured, assigned, and labeled transitions were analyzed from more than 100 sources. The measured lines come from one-photon spectra recorded at room temperature in absorption, from hot samples with temperatures up to 3000K recorded in emission, and from multiresonance excitation spectra which sample levels up to dissociation. The total number of transitions considered is 184667 of which 182156 are validated: 68027 between para states and 114129 ortho ones. These transitions give rise to 18486 validated energy levels, of which 10446 and 8040 belong to o-H216O and p-H216O, respectively. The energy levels, including their labeling with approximate normal-mode and rigid-rotor quantum numbers, have been checked against ones determined from accurate variational nuclear motion computations employing exact kinetic energy operators as well as against previous compilations of energy levels. The extensive list of MARVEL lines and levels obtained are deposited in the supplementary data of this paper, as well as in a distributed information system applied to water, W@DIS, where they can easily be retrieved

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

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    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 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.Comment: Accepted for publication in Pure and Applied Chemistr

    High sensitivity ICLAS of H 2 18 O between 13 540 and 14 100 cm -1

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    International audienceThe high resolution absorption spectrum of 18O enriched water was recorded between 13 540 and 14 100 cm -1 by high sensitivity Intracavity Laser Absorption Spectroscopy (ICLAS). This spectral region corresponds to the relatively strong 4ν polyad. Four isotopologues of water (H 218O, H 216O, H 217O, HD 18O) are found to contribute to the spectrum. About 1800 H 218O lines were assigned by comparison with variational calculations. Altogether, 855 accurate energy levels of H 218O were determined from transitions attributed to 23 upper vibrational states, 342 of them being reported for the first time. New information includes 84 energy levels of H 217O present with a 1.5% relative concentration in the sample and the rotational structure of the 4ν 3 band of HD 18O at 13814.520 cm -1. By comparison with variational calculations and with ICLAS absolute intensity values, a systematic overestimation by about 25% has been evidenced for the H 218O intensity values included in the HITRAN database for the 12 400-14 520 cm -1 range

    Communication processes and modern society

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    The article targets specific features of modern economic and communication processes, the ones being most obviously revealed in such integral spheres of modern environment as social relations and service sector, as well as their connection with communicative space of today’s social media. It focuses on ways to assess the role and place of mass-communication processes in optimization and development of social processes. It is conducted to ascertain the influence of major actors on modern society

    ICLAS of HDO between 13020 and 14115 cm-1

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    International audienceThe high resolution absorption spectrum of monodeuterated water, HDO, has been recorded by Intracavity Laser Absorption Spectroscopy (ICLAS) in the 13020-14115 cm-1 region dominated by the 43 band. The achieved noise equivalent absorption (min~ 10-9 cm-1) allowed detecting transitions with line strengths as small as 2Ă—10-27 cm/molecule which is about 10 times lower than the smallest line intensities previously detected in the region. The rovibrational assignment of the spectrum was based on the results of the variational calculations of Schwenke and Partridge (SP) as well as recent calculations using a new potential energy surface performed by Voronin, Tolchenov and Tennyson (VTT). 2157 transitions involving 21 upper vibrational states were assigned to HD16O while only four bands were previously reported in the region. A set of 157 new energy levels could be derived. It includes rotational levels of several highly excited bending states, in particular the (0 11 0) pure bending state. For some states like the (103) and (023) Fermi dyad, effective Hamiltonian modelling was needed to establish the vibrational assignments of some rotational levels. VTT calculations were found to significantly improve SP results, the rms deviation of the calculated and observed energies being decreased from 0.23 to 0.06 cm-1. Finally, 79 transitions of the 43 band of the HD18O isotopologue were assigned, leading to the derivation of 48 levels which are the most excited energy levels reported so far for this isotopologue
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