Democratic particle motion for metabasin transitions in simple glass formers.
We use molecular dynamics computer simulations to investigate the local motion of the particles in a supercooled binary liquid. Using the concept of the distance matrix, we find that the alpha relaxation corresponds to a small number of crossings from one metabasin to a neighboring one. Each crossing is very rapid and involves the collective motion of O(40) particles that form a relatively compact cluster, whereas stringlike motions seem not to be relevant for these transitions. These compact clusters are thus potential candidates for the cooperatively rearranging regions proposed a long time ago by Adam and Gibbs.
Laboratorio de Fisicoquímica, Departamento de Química, Universidad Nacional del Sur, Avenida Alem 1253, 8000 Bahía Blanca, Argentina.
G A
GA
Appignanesi
J A
JA
Rodríguez Fris
R A
RA
Montani
W
W
Kob