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Probing excitations and cooperatively rearranging regions in deeply supercooled liquids

Upon approaching the glass transition, the relaxation of supercooled liquids is controlled by activated processes, which become dominant at temperatures below the so-called dynamical crossover predicted by Mode Coupling theory (MCT). Two of the main frameworks rationalising this behaviour are dynami...

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Autores principales: Ortlieb, Levke, Ingebrigtsen, Trond S., Hallett, James E., Turci, Francesco, Royall, C. Patrick
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10163050/
https://www.ncbi.nlm.nih.gov/pubmed/37147284
http://dx.doi.org/10.1038/s41467-023-37793-2
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author Ortlieb, Levke
Ingebrigtsen, Trond S.
Hallett, James E.
Turci, Francesco
Royall, C. Patrick
author_facet Ortlieb, Levke
Ingebrigtsen, Trond S.
Hallett, James E.
Turci, Francesco
Royall, C. Patrick
author_sort Ortlieb, Levke
collection PubMed
description Upon approaching the glass transition, the relaxation of supercooled liquids is controlled by activated processes, which become dominant at temperatures below the so-called dynamical crossover predicted by Mode Coupling theory (MCT). Two of the main frameworks rationalising this behaviour are dynamic facilitation theory (DF) and the thermodynamic scenario which give equally good descriptions of the available data. Only particle-resolved data from liquids supercooled below the MCT crossover can reveal the microscopic mechanism of relaxation. By employing state-of-the-art GPU simulations and nano-particle resolved colloidal experiments, we identify the elementary units of relaxation in deeply supercooled liquids. Focusing on the excitations of DF and cooperatively rearranging regions (CRRs) implied by the thermodynamic scenario, we find that several predictions of both hold well below the MCT crossover: for the elementary excitations, their density follows a Boltzmann law, and their timescales converge at low temperatures. For CRRs, the decrease in bulk configurational entropy is accompanied by the increase of their fractal dimension. While the timescale of excitations remains microscopic, that of CRRs tracks a timescale associated with dynamic heterogeneity, [Formula: see text] . This timescale separation of excitations and CRRs opens the possibility of accumulation of excitations giving rise to cooperative behaviour leading to CRRs.
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spelling pubmed-101630502023-05-07 Probing excitations and cooperatively rearranging regions in deeply supercooled liquids Ortlieb, Levke Ingebrigtsen, Trond S. Hallett, James E. Turci, Francesco Royall, C. Patrick Nat Commun Article Upon approaching the glass transition, the relaxation of supercooled liquids is controlled by activated processes, which become dominant at temperatures below the so-called dynamical crossover predicted by Mode Coupling theory (MCT). Two of the main frameworks rationalising this behaviour are dynamic facilitation theory (DF) and the thermodynamic scenario which give equally good descriptions of the available data. Only particle-resolved data from liquids supercooled below the MCT crossover can reveal the microscopic mechanism of relaxation. By employing state-of-the-art GPU simulations and nano-particle resolved colloidal experiments, we identify the elementary units of relaxation in deeply supercooled liquids. Focusing on the excitations of DF and cooperatively rearranging regions (CRRs) implied by the thermodynamic scenario, we find that several predictions of both hold well below the MCT crossover: for the elementary excitations, their density follows a Boltzmann law, and their timescales converge at low temperatures. For CRRs, the decrease in bulk configurational entropy is accompanied by the increase of their fractal dimension. While the timescale of excitations remains microscopic, that of CRRs tracks a timescale associated with dynamic heterogeneity, [Formula: see text] . This timescale separation of excitations and CRRs opens the possibility of accumulation of excitations giving rise to cooperative behaviour leading to CRRs. Nature Publishing Group UK 2023-05-05 /pmc/articles/PMC10163050/ /pubmed/37147284 http://dx.doi.org/10.1038/s41467-023-37793-2 Text en © The Author(s) 2023 https://creativecommons.org/licenses/by/4.0/Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Article
Ortlieb, Levke
Ingebrigtsen, Trond S.
Hallett, James E.
Turci, Francesco
Royall, C. Patrick
Probing excitations and cooperatively rearranging regions in deeply supercooled liquids
title Probing excitations and cooperatively rearranging regions in deeply supercooled liquids
title_full Probing excitations and cooperatively rearranging regions in deeply supercooled liquids
title_fullStr Probing excitations and cooperatively rearranging regions in deeply supercooled liquids
title_full_unstemmed Probing excitations and cooperatively rearranging regions in deeply supercooled liquids
title_short Probing excitations and cooperatively rearranging regions in deeply supercooled liquids
title_sort probing excitations and cooperatively rearranging regions in deeply supercooled liquids
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10163050/
https://www.ncbi.nlm.nih.gov/pubmed/37147284
http://dx.doi.org/10.1038/s41467-023-37793-2
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