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

Abstract

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.

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Affiliated Institutions

• Czech Academy of Sciences, Institute of Physics CZ
• Centre National de la Recherche Scientifique FR
• Institut Pierre-Simon Laplace FR
• Université Paris Cité FR
• Groupe de Spectrométrie Moléculaire et Atmosphérique FR
• National Institute of Standards and Technology US
• Center for Astrophysics Harvard & Smithsonian US
• Laboratoire de Physique des Lasers, Atomes et Molécules FR
• Paris-Est Sup FR
• Eötvös Loránd University HU
• National Institute of Standards EG
• University College London GB
• Laboratoire Interuniversitaire des Systèmes Atmosphériques FR
• National University US
• Université Paris-Est Créteil FR
• Nicolaus Copernicus University PL
• University of Massachusetts Lowell US
• University of Campania "Luigi Vanvitelli" IT
• Interface (United States) US

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