Experimental evidence by neutron scattering of a crossover from Gaussian to non-Gaussian behavior in the α relaxation of polyisoprene

We report incoherent quasielastic neutron scattering experiments exploring the α-relaxation range in polyisoprene over an unprecedented range in momentum transfer Q. The data corroborate and validate earlier molecular dynamics simulations and reveal the existence of a crossover from Gaussian to non-...

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Autores: Arbe, Arantxa, Colmenero de León, Juan, Álvarez González, Fernando, Monkenbusch, Michael, Richter, Dieter, Farago, Bela, Frick, Bernhard
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2003
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/224671
Acceso en línea:http://hdl.handle.net/10261/224671
Access Level:acceso abierto
Palabra clave:ddc:530
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spelling Experimental evidence by neutron scattering of a crossover from Gaussian to non-Gaussian behavior in the α relaxation of polyisopreneArbe, ArantxaColmenero de León, JuanÁlvarez González, FernandoMonkenbusch, MichaelRichter, DieterFarago, BelaFrick, Bernhardddc:530We report incoherent quasielastic neutron scattering experiments exploring the α-relaxation range in polyisoprene over an unprecedented range in momentum transfer Q. The data corroborate and validate earlier molecular dynamics simulations and reveal the existence of a crossover from Gaussian to non-Gaussian character of the main chain protons self-correlation function in the α-relaxation regime. The real challenge of the experiment was to push the neutron techniques to cover a Q range as wide as possible. By combining two neutron spin echo spectrometers and a backscattering instrument, we have been able to study the dynamics in a Q range of 0.1<~Q<~4.7Å−1. In the low- Q regime the shape of the relaxation function was found to be related to the dispersion of the relaxation times as predicted by the Gaussian assumption. At short distances or large Q, this relationship is strongly violated indicating a non-Gaussian regime. We have performed a detailed comparison between the experiments and simulations at different temperatures and found, apart from a temperature shift, complete agreement. Combining experiments and simulations led to a consistent interpretation in terms of a distribution of jumps underlying the diffusive motion of protons in the α process. This model leads to a time-dependent non-Gaussianity parameter that agrees nearly quantitatively with the simulations and exhibits all features resolved so far from various simulations.A.A., J.C., and F.A. acknowledge support from the following Project Nos.: DGICYT, PB97-0638; GV, EX 1998-23; UPV/EHU, 206.215-G20/98; 9/UPV 00206.215-13568/2001. Support from ‘‘Donostia International Physics Center’’ is also acknowledged by A.A., J.C., F.A., and D.RPeer reviewedAmerican Physical SocietyDonostia International Physics CenterEusko JaurlaritzaUniversidad del País VascoDirección General de Investigación Científica y Técnica, DGICT (España)Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]202020202003info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/224671reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttps://doi.org/10.1103/PhysRevE.67.051802Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/2246712026-05-22T06:33:51Z
dc.title.none.fl_str_mv Experimental evidence by neutron scattering of a crossover from Gaussian to non-Gaussian behavior in the α relaxation of polyisoprene
title Experimental evidence by neutron scattering of a crossover from Gaussian to non-Gaussian behavior in the α relaxation of polyisoprene
spellingShingle Experimental evidence by neutron scattering of a crossover from Gaussian to non-Gaussian behavior in the α relaxation of polyisoprene
Arbe, Arantxa
ddc:530
title_short Experimental evidence by neutron scattering of a crossover from Gaussian to non-Gaussian behavior in the α relaxation of polyisoprene
title_full Experimental evidence by neutron scattering of a crossover from Gaussian to non-Gaussian behavior in the α relaxation of polyisoprene
title_fullStr Experimental evidence by neutron scattering of a crossover from Gaussian to non-Gaussian behavior in the α relaxation of polyisoprene
title_full_unstemmed Experimental evidence by neutron scattering of a crossover from Gaussian to non-Gaussian behavior in the α relaxation of polyisoprene
title_sort Experimental evidence by neutron scattering of a crossover from Gaussian to non-Gaussian behavior in the α relaxation of polyisoprene
dc.creator.none.fl_str_mv Arbe, Arantxa
Colmenero de León, Juan
Álvarez González, Fernando
Monkenbusch, Michael
Richter, Dieter
Farago, Bela
Frick, Bernhard
author Arbe, Arantxa
author_facet Arbe, Arantxa
Colmenero de León, Juan
Álvarez González, Fernando
Monkenbusch, Michael
Richter, Dieter
Farago, Bela
Frick, Bernhard
author_role author
author2 Colmenero de León, Juan
Álvarez González, Fernando
Monkenbusch, Michael
Richter, Dieter
Farago, Bela
Frick, Bernhard
author2_role author
author
author
author
author
author
dc.contributor.none.fl_str_mv Donostia International Physics Center
Eusko Jaurlaritza
Universidad del País Vasco
Dirección General de Investigación Científica y Técnica, DGICT (España)
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv ddc:530
topic ddc:530
description We report incoherent quasielastic neutron scattering experiments exploring the α-relaxation range in polyisoprene over an unprecedented range in momentum transfer Q. The data corroborate and validate earlier molecular dynamics simulations and reveal the existence of a crossover from Gaussian to non-Gaussian character of the main chain protons self-correlation function in the α-relaxation regime. The real challenge of the experiment was to push the neutron techniques to cover a Q range as wide as possible. By combining two neutron spin echo spectrometers and a backscattering instrument, we have been able to study the dynamics in a Q range of 0.1<~Q<~4.7Å−1. In the low- Q regime the shape of the relaxation function was found to be related to the dispersion of the relaxation times as predicted by the Gaussian assumption. At short distances or large Q, this relationship is strongly violated indicating a non-Gaussian regime. We have performed a detailed comparison between the experiments and simulations at different temperatures and found, apart from a temperature shift, complete agreement. Combining experiments and simulations led to a consistent interpretation in terms of a distribution of jumps underlying the diffusive motion of protons in the α process. This model leads to a time-dependent non-Gaussianity parameter that agrees nearly quantitatively with the simulations and exhibits all features resolved so far from various simulations.
publishDate 2003
dc.date.none.fl_str_mv 2003
2020
2020
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Publisher's version
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/224671
url http://hdl.handle.net/10261/224671
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv https://doi.org/10.1103/PhysRevE.67.051802
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv American Physical Society
publisher.none.fl_str_mv American Physical Society
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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