Volume 67, Number 5, September 2004
|Page(s)||820 - 826|
|Section||Condensed matter: structure, mechanical and thermal properties|
|Published online||01 August 2004|
Dynamics of a rigid rod in a glassy medium
Laboratoire des Verres, Université de Montpellier II Place E. Bataillon, CC 069, F-34095 Montpellier, France
2 Dipartimento di Fisica and INFM Udr and Center for Statistical Mechanics and Complexity, Università di Roma “La Sapienza” Piazzale Aldo Moro 2, I-00185 Roma, Italy
Accepted: 21 June 2004
We present simulations of the motion of a single rigid rod in a disordered static 2d array of disk-like obstacles. The rotational, , and center-of-mass translational, , diffusion constants are calculated for a wide range of rod length L and density of obstacles ρ . It is found that follows the behavior predicted by kinetic theory for a hard disk with an effective radius . A dynamic crossover is observed in for L comparable to the typical distance between neighboring obstacles . Using arguments from kinetic theory and reptation, we rationalize the scaling laws, dynamic exponents, and prefactors observed for . In analogy with the enhanced translational diffusion observed in deeply supercooled liquids, the Stokes-Einstein-Debye relation is violated for .
PACS: 66.30.-h – Diffusion in solids / 05.40.-a – Fluctuation phenomena, random processes, noise, and Brownian motion / 64.70.Pf – Glass transitions
© EDP Sciences, 2004
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.