The role of vibrational anharmonicity in the computational study of thermal spin crossover

Spin crossover in transition metal complexes can be studied in great detail with computational chemistry. Over the years, the understanding has grown that the relative stability of high-spin (HS) versus low-spin (LS) states is a subtle balance of many factors that all need to be taken into account f...

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Autores: Wu, Jianfang, Sousa Romero, Carmen, Graaf, Coen de
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2019
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/150763
Acceso en línea:https://hdl.handle.net/2445/150763
Access Level:acceso abierto
Palabra clave:Compostos de metalls de transició
Teoria quàntica
Spin (Física nuclear)
Transition metal compounds
Quantum theory
Nuclear spin
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spelling The role of vibrational anharmonicity in the computational study of thermal spin crossoverWu, JianfangSousa Romero, CarmenGraaf, Coen deCompostos de metalls de transicióTeoria quànticaSpin (Física nuclear)Transition metal compoundsQuantum theoryNuclear spinSpin crossover in transition metal complexes can be studied in great detail with computational chemistry. Over the years, the understanding has grown that the relative stability of high-spin (HS) versus low-spin (LS) states is a subtle balance of many factors that all need to be taken into account for a reliable description. Among the different contributions, the zero-point energy (ZPE) and the entropy play key roles. These quantities are usually calculated assuming a harmonic oscillator model for the molecular vibrations. We investigated the impact of including anharmonic corrections on the ZPE and the entropy and indirectly on the critical temperature of spin crossover. As test systems, we used a set of ten Fe(II) complexes and one Fe(III) complex, covering different coordination modes (mono-, bi-, and tri-dentate ligands), decreasing coordination number upon spin crossover, coordination by second- and third-row atoms, and changes in the oxidation state. The results show that the anharmonicity has a measurable effect, but it is in general rather small, and tendencies are not easily recognized. As a conclusion, we put forward that for high precision results, one should be aware of the anharmonic effects, but as long as computational chemistry is still struggling with other larger factors like the influence of the environment and the accurate determination of the electronic energy difference between HS and LS, the anharmonicity of the vibrational modes is a minor concern.MDPI2019info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2445/150763Articles publicats en revistes (Ciència dels Materials i Química Física)reponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaInglésReproducció del document publicat a: https://doi.org/10.3390/magnetochemistry5030049Magnetochemistry, 2019, vol. 5, num. 49https://doi.org/10.3390/magnetochemistry5030049cc-by (c) Wu, Jianfang et al., 2019http://creativecommons.org/licenses/by/3.0/esinfo:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/1507632026-05-27T06:46:51Z
dc.title.none.fl_str_mv The role of vibrational anharmonicity in the computational study of thermal spin crossover
title The role of vibrational anharmonicity in the computational study of thermal spin crossover
spellingShingle The role of vibrational anharmonicity in the computational study of thermal spin crossover
Wu, Jianfang
Compostos de metalls de transició
Teoria quàntica
Spin (Física nuclear)
Transition metal compounds
Quantum theory
Nuclear spin
title_short The role of vibrational anharmonicity in the computational study of thermal spin crossover
title_full The role of vibrational anharmonicity in the computational study of thermal spin crossover
title_fullStr The role of vibrational anharmonicity in the computational study of thermal spin crossover
title_full_unstemmed The role of vibrational anharmonicity in the computational study of thermal spin crossover
title_sort The role of vibrational anharmonicity in the computational study of thermal spin crossover
dc.creator.none.fl_str_mv Wu, Jianfang
Sousa Romero, Carmen
Graaf, Coen de
author Wu, Jianfang
author_facet Wu, Jianfang
Sousa Romero, Carmen
Graaf, Coen de
author_role author
author2 Sousa Romero, Carmen
Graaf, Coen de
author2_role author
author
dc.subject.none.fl_str_mv Compostos de metalls de transició
Teoria quàntica
Spin (Física nuclear)
Transition metal compounds
Quantum theory
Nuclear spin
topic Compostos de metalls de transició
Teoria quàntica
Spin (Física nuclear)
Transition metal compounds
Quantum theory
Nuclear spin
description Spin crossover in transition metal complexes can be studied in great detail with computational chemistry. Over the years, the understanding has grown that the relative stability of high-spin (HS) versus low-spin (LS) states is a subtle balance of many factors that all need to be taken into account for a reliable description. Among the different contributions, the zero-point energy (ZPE) and the entropy play key roles. These quantities are usually calculated assuming a harmonic oscillator model for the molecular vibrations. We investigated the impact of including anharmonic corrections on the ZPE and the entropy and indirectly on the critical temperature of spin crossover. As test systems, we used a set of ten Fe(II) complexes and one Fe(III) complex, covering different coordination modes (mono-, bi-, and tri-dentate ligands), decreasing coordination number upon spin crossover, coordination by second- and third-row atoms, and changes in the oxidation state. The results show that the anharmonicity has a measurable effect, but it is in general rather small, and tendencies are not easily recognized. As a conclusion, we put forward that for high precision results, one should be aware of the anharmonic effects, but as long as computational chemistry is still struggling with other larger factors like the influence of the environment and the accurate determination of the electronic energy difference between HS and LS, the anharmonicity of the vibrational modes is a minor concern.
publishDate 2019
dc.date.none.fl_str_mv 2019
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/150763
url https://hdl.handle.net/2445/150763
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Reproducció del document publicat a: https://doi.org/10.3390/magnetochemistry5030049
Magnetochemistry, 2019, vol. 5, num. 49
https://doi.org/10.3390/magnetochemistry5030049
dc.rights.none.fl_str_mv cc-by (c) Wu, Jianfang et al., 2019
http://creativecommons.org/licenses/by/3.0/es
info:eu-repo/semantics/openAccess
rights_invalid_str_mv cc-by (c) Wu, Jianfang et al., 2019
http://creativecommons.org/licenses/by/3.0/es
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv MDPI
publisher.none.fl_str_mv MDPI
dc.source.none.fl_str_mv Articles publicats en revistes (Ciència dels Materials i Química Física)
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
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