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New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium

The question of whether mesospheric OH(υ) rotational population distributions are in equilibrium with the local kinetic temperature has been debated over several decades. Despite several indications for the existence of non-equilibrium effects, the general consensus has been that emissions originati...

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Autores principales: Kalogerakis, Konstantinos S., Matsiev, Daniel, Cosby, Philip C., Dodd, James A., Falcinelli, Stefano, Hedin, Jonas, Kutepov, Alexander A., Noll, Stefan, Panka, Peter A., Romanescu, Constantin, Thiebaud, Jérôme E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5833932/
https://www.ncbi.nlm.nih.gov/pubmed/29503514
http://dx.doi.org/10.5194/angeo-36-13-2018
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author Kalogerakis, Konstantinos S.
Matsiev, Daniel
Cosby, Philip C.
Dodd, James A.
Falcinelli, Stefano
Hedin, Jonas
Kutepov, Alexander A.
Noll, Stefan
Panka, Peter A.
Romanescu, Constantin
Thiebaud, Jérôme E.
author_facet Kalogerakis, Konstantinos S.
Matsiev, Daniel
Cosby, Philip C.
Dodd, James A.
Falcinelli, Stefano
Hedin, Jonas
Kutepov, Alexander A.
Noll, Stefan
Panka, Peter A.
Romanescu, Constantin
Thiebaud, Jérôme E.
author_sort Kalogerakis, Konstantinos S.
collection PubMed
description The question of whether mesospheric OH(υ) rotational population distributions are in equilibrium with the local kinetic temperature has been debated over several decades. Despite several indications for the existence of non-equilibrium effects, the general consensus has been that emissions originating from low rotational levels are thermalized. Sky spectra simultaneously observing several vibrational levels demonstrated reproducible trends in the extracted OH(υ) rotational temperatures as a function of vibrational excitation. Laboratory experiments provided information on rotational energy transfer and direct evidence for fast multi-quantum OH(high-υ) vibrational relaxation by O atoms. We examine the relationship of the new relaxation pathways with the behavior exhibited by OH(υ) rotational population distributions. Rapid OH(high-υ) + O multi-quantum vibrational relaxation connects high and low vibrational levels and enhances the hot tail of the OH(low-υ) rotational distributions. The effective rotational temperatures of mesospheric OH(υ) are found to deviate from local thermodynamic equilibrium for all observed vibrational levels.
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spelling pubmed-58339322018-03-02 New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium Kalogerakis, Konstantinos S. Matsiev, Daniel Cosby, Philip C. Dodd, James A. Falcinelli, Stefano Hedin, Jonas Kutepov, Alexander A. Noll, Stefan Panka, Peter A. Romanescu, Constantin Thiebaud, Jérôme E. Ann Geophys Article The question of whether mesospheric OH(υ) rotational population distributions are in equilibrium with the local kinetic temperature has been debated over several decades. Despite several indications for the existence of non-equilibrium effects, the general consensus has been that emissions originating from low rotational levels are thermalized. Sky spectra simultaneously observing several vibrational levels demonstrated reproducible trends in the extracted OH(υ) rotational temperatures as a function of vibrational excitation. Laboratory experiments provided information on rotational energy transfer and direct evidence for fast multi-quantum OH(high-υ) vibrational relaxation by O atoms. We examine the relationship of the new relaxation pathways with the behavior exhibited by OH(υ) rotational population distributions. Rapid OH(high-υ) + O multi-quantum vibrational relaxation connects high and low vibrational levels and enhances the hot tail of the OH(low-υ) rotational distributions. The effective rotational temperatures of mesospheric OH(υ) are found to deviate from local thermodynamic equilibrium for all observed vibrational levels. 2018-01-09 2018 /pmc/articles/PMC5833932/ /pubmed/29503514 http://dx.doi.org/10.5194/angeo-36-13-2018 Text en http://creativecommons.org/licenses/by/4.0/ This work is distributed under the Creative Commons Attribution 4.0 License.
spellingShingle Article
Kalogerakis, Konstantinos S.
Matsiev, Daniel
Cosby, Philip C.
Dodd, James A.
Falcinelli, Stefano
Hedin, Jonas
Kutepov, Alexander A.
Noll, Stefan
Panka, Peter A.
Romanescu, Constantin
Thiebaud, Jérôme E.
New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium
title New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium
title_full New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium
title_fullStr New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium
title_full_unstemmed New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium
title_short New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium
title_sort new insights for mesospheric oh: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5833932/
https://www.ncbi.nlm.nih.gov/pubmed/29503514
http://dx.doi.org/10.5194/angeo-36-13-2018
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