Understanding the destruction of CH+ with atomic hydrogen at low temperatures: a non-adiabatic dynamical study

[EN]Carbon hydrides play a crucial role in the formation of complex organic molecules in highly UV illuminated regions of the interstellar medium (ISM). The formation of CH+ is the first step in the reactions leading to the formation of various carbon hydrides. CH+ formation is relatively well under...

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Detalles Bibliográficos
Autores: Mazo Sevillano, Pablo del, Aguado, Alfredo, Lique, François, Jara-Toro, Rafael A., Roncero, Octavio
Tipo de recurso: artículo
Estado:Versión borrador
Fecha de publicación:2025
País:España
Institución:Universidad de Salamanca (USAL)
Repositorio:GREDOS. Repositorio Institucional de la Universidad de Salamanca
OAI Identifier:oai:gredos.usal.es:10366/170282
Acceso en línea:http://hdl.handle.net/10366/170282
Access Level:acceso abierto
Palabra clave:Astrochemistry
Non-adiabatic
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spelling Understanding the destruction of CH+ with atomic hydrogen at low temperatures: a non-adiabatic dynamical studyMazo Sevillano, Pablo delAguado, AlfredoLique, FrançoisJara-Toro, Rafael A.Roncero, OctavioAstrochemistryNon-adiabatic[EN]Carbon hydrides play a crucial role in the formation of complex organic molecules in highly UV illuminated regions of the interstellar medium (ISM). The formation of CH+ is the first step in the reactions leading to the formation of various carbon hydrides. CH+ formation is relatively well understood with strong agreement between theoretical and experimental results. However, its destruction by collision with the H atom, at low temperatures of interest in the ISM, is in contrast still not well understood and there is a large discrepancy between theoretical and experimental data [R. Plasil et al., AstroPhys. J., 2011, 737, 1], which are almost an order of magnitude smaller than various classical and quantum mechanical calculations. In this work we have computed and fitted a new set of non-adiabatic potential energy surfaces (PES) for the title system, including the three lower adiabatic states. We then investigate three possible sources of disagreement with the experimental results: non-adiabatic effects from regions near the conical intersections, and rotational and vibrational excitation of the CH+ molecule. We conclude that vibrational excitation of the CH+ plays a major role in reducing the reactivity at low temperatures, and we raise the question of whether vibrational thermalization of the CH+ is not fully achieved in the experiment. Such non-thermalized conditions could explain the decrease of the measured reaction rate constant.The Royal Society of Chemistry202620262025info:eu-repo/semantics/articleinfo:eu-repo/semantics/draftapplication/pdfhttp://hdl.handle.net/10366/170282reponame:GREDOS. Repositorio Institucional de la Universidad de Salamancainstname:Universidad de Salamanca (USAL)InglésPID2021-122549NB-C21PID2021-122549NB-C22Attribution-NonCommercial-NoDerivs 3.0 Unportedhttp://creativecommons.org/licenses/by-nc-nd/3.0/info:eu-repo/semantics/openAccessoai:gredos.usal.es:10366/1702822026-06-07T06:28:51Z
dc.title.none.fl_str_mv Understanding the destruction of CH+ with atomic hydrogen at low temperatures: a non-adiabatic dynamical study
title Understanding the destruction of CH+ with atomic hydrogen at low temperatures: a non-adiabatic dynamical study
spellingShingle Understanding the destruction of CH+ with atomic hydrogen at low temperatures: a non-adiabatic dynamical study
Mazo Sevillano, Pablo del
Astrochemistry
Non-adiabatic
title_short Understanding the destruction of CH+ with atomic hydrogen at low temperatures: a non-adiabatic dynamical study
title_full Understanding the destruction of CH+ with atomic hydrogen at low temperatures: a non-adiabatic dynamical study
title_fullStr Understanding the destruction of CH+ with atomic hydrogen at low temperatures: a non-adiabatic dynamical study
title_full_unstemmed Understanding the destruction of CH+ with atomic hydrogen at low temperatures: a non-adiabatic dynamical study
title_sort Understanding the destruction of CH+ with atomic hydrogen at low temperatures: a non-adiabatic dynamical study
dc.creator.none.fl_str_mv Mazo Sevillano, Pablo del
Aguado, Alfredo
Lique, François
Jara-Toro, Rafael A.
Roncero, Octavio
author Mazo Sevillano, Pablo del
author_facet Mazo Sevillano, Pablo del
Aguado, Alfredo
Lique, François
Jara-Toro, Rafael A.
Roncero, Octavio
author_role author
author2 Aguado, Alfredo
Lique, François
Jara-Toro, Rafael A.
Roncero, Octavio
author2_role author
author
author
author
dc.subject.none.fl_str_mv Astrochemistry
Non-adiabatic
topic Astrochemistry
Non-adiabatic
description [EN]Carbon hydrides play a crucial role in the formation of complex organic molecules in highly UV illuminated regions of the interstellar medium (ISM). The formation of CH+ is the first step in the reactions leading to the formation of various carbon hydrides. CH+ formation is relatively well understood with strong agreement between theoretical and experimental results. However, its destruction by collision with the H atom, at low temperatures of interest in the ISM, is in contrast still not well understood and there is a large discrepancy between theoretical and experimental data [R. Plasil et al., AstroPhys. J., 2011, 737, 1], which are almost an order of magnitude smaller than various classical and quantum mechanical calculations. In this work we have computed and fitted a new set of non-adiabatic potential energy surfaces (PES) for the title system, including the three lower adiabatic states. We then investigate three possible sources of disagreement with the experimental results: non-adiabatic effects from regions near the conical intersections, and rotational and vibrational excitation of the CH+ molecule. We conclude that vibrational excitation of the CH+ plays a major role in reducing the reactivity at low temperatures, and we raise the question of whether vibrational thermalization of the CH+ is not fully achieved in the experiment. Such non-thermalized conditions could explain the decrease of the measured reaction rate constant.
publishDate 2025
dc.date.none.fl_str_mv 2025
2026
2026
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/draft
format article
status_str draft
dc.identifier.none.fl_str_mv http://hdl.handle.net/10366/170282
url http://hdl.handle.net/10366/170282
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv PID2021-122549NB-C21
PID2021-122549NB-C22
dc.rights.none.fl_str_mv Attribution-NonCommercial-NoDerivs 3.0 Unported
http://creativecommons.org/licenses/by-nc-nd/3.0/
info:eu-repo/semantics/openAccess
rights_invalid_str_mv Attribution-NonCommercial-NoDerivs 3.0 Unported
http://creativecommons.org/licenses/by-nc-nd/3.0/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv The Royal Society of Chemistry
publisher.none.fl_str_mv The Royal Society of Chemistry
dc.source.none.fl_str_mv reponame:GREDOS. Repositorio Institucional de la Universidad de Salamanca
instname:Universidad de Salamanca (USAL)
instname_str Universidad de Salamanca (USAL)
reponame_str GREDOS. Repositorio Institucional de la Universidad de Salamanca
collection GREDOS. Repositorio Institucional de la Universidad de Salamanca
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.81155

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