INVESTIGADORES
FRECHERO marisa Alejandra
artículos
Título:
Particle mobility and metabasin exploration in model glass-formers.
Autor/es:
G. A. APPIGNANESI; M. A. FRECHERO; L. M. ALARCÓN
Revista:
PHYSICA A - STATISTICAL AND THEORETICAL PHYSICS
Referencias:
Año: 2007 vol. 374 p. 229 - 238
ISSN:
0378-4371
Resumen:
Particle mobility and metabasin exploration in
model glass-formers
G.A. Appignanesi, M.A. Frechero, L.M. Alarco´ n, M.A. Frechero, L.M. Alarco´ n
Laboratorio de Fisicoquý´mica, Departamento de Quý´mica, Universidad Nacional del Sur (UNS),
Av. Alem 1253 (8000) Bahý´a Blanca, Argentina
Received 11 January 2006; received in revised form 9 June 2006
Available online 28 July 2006
Abstract
In this work, we assess the relevance of different range particle displacements and string motions to the metabasin (MB)
dynamics of a simple glass former. We find that MB transitions are triggered by the occurrence of massive rearrangements
termed as democratic clusters or d-clusters which last on average less than 1% of the a-relaxation time. Thus, at variance
from previous investigations that focused on large displacements and strings, our work points to the essential role of
medium-range particle displacements: we find that d-clusters are compact objects since the local neighborhoods of the most
mobile particles exhibit significant rearrangements with a clear prevalence of medium-range displacements (of around 20%
of the interparticle distance). This is in contrast to the string-like movements for which we demonstrate that many of them
fully develop in isolation (their local environment being mostly insensitive to them) and at times different from that of MB
transitions, being thus irrelevant to the a-relaxation. Additionally, from the analysis of the MB dynamics, preliminary
support to the dynamics facilitation scenario is provided.a-relaxation time. Thus, at variance
from previous investigations that focused on large displacements and strings, our work points to the essential role of
medium-range particle displacements: we find that d-clusters are compact objects since the local neighborhoods of the most
mobile particles exhibit significant rearrangements with a clear prevalence of medium-range displacements (of around 20%
of the interparticle distance). This is in contrast to the string-like movements for which we demonstrate that many of them
fully develop in isolation (their local environment being mostly insensitive to them) and at times different from that of MB
transitions, being thus irrelevant to the a-relaxation. Additionally, from the analysis of the MB dynamics, preliminary
support to the dynamics facilitation scenario is provided.a-relaxation. Additionally, from the analysis of the MB dynamics, preliminary
support to the dynamics facilitation scenario is provided.
r 2006 Elsevier B.V. All rights reserved.2006 Elsevier B.V. All rights reserved.
Keywords: Glass transition; Molecular dynamics; Supercooled liquidsGlass transition; Molecular dynamics; Supercooled liquids