INVESTIGADORES
APPIGNANESI Gustavo Adrian
artículos
Título:
Mechanistic view of the relaxation dynamics of a simple glass-former. A bridge between the topographic and the dynamic approaches
Autor/es:
G.A. APPIGNANESI AND R.A. MONTANI
Revista:
JOURNAL OF NON-CRYSTALLINE SOLIDS
Editorial:
Elsevier
Referencias:
Año: 2004 vol. 337 p. 109 - 114
ISSN:
0022-3093
Resumen:
We provide a link between the two main approaches to the relaxation dynamics of glassy systems: The real dynamics scheme
and the inherent dynamics or topographic formalism. The first approach is based on molecular dynamics (MD) simulations, whilst
the second one reflects the underlying influence of the energy landscape (within a timescale separation and activated dynamics
scenario) and constitutes a widespread picture within the realm of complex systems ranging from glasses to biopolymers. For a
model glass-former (a binary Lennard-Jones system), MD studies which characterized in detail the movements of the different
particles led to the discovery of dynamical heterogeneities. On the other hand, the topographic approach identified activated events
on the potential energy surface of this system corresponding to transitions between different basins of attraction or inherent
structures. In this work we demonstrate that at low temperature the relevant events identified by both methods conform to a basic
mechanistic phenomenology with elementary steps involving ballistic string-like particle movements. We also show that as temperature
increases and the timescales characterizing events of different range become comparable, these elemental steps loose their
nature of rare activated events. Concurrently, the system looses diversity and complexity, signatures of glassy behavior. This fact
enables us to furnish for the first time the microscopic structural and dynamical basis and conditions for the prevalence of the
landscape paradigm for this class of systems.