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Anomalous diffusion in supercooled liquids: a long-range localization in particle trajectories
1Department of Numerical Analysis and Computer Science, Royal Institute of Technology, S-100 44 Stockholm, Sweden. tomaso@nada.kth.se
The Journal of Chemical Physics
|August 7, 2009
Summary
Particle trajectories in supercooled liquids reveal three diffusion regimes, including a novel long-range localization anomaly. This finding offers insights into the potential-energy landscape and diffusion dynamics in glass-forming materials.
Area of Science:
- Condensed matter physics
- Statistical mechanics
- Computational materials science
Background:
- Supercooled liquids exhibit complex particle dynamics.
- Understanding diffusion mechanisms is crucial for materials science.
- Glass-forming liquids present unique challenges in characterizing dynamics.
Purpose of the Study:
- To statistically analyze particle trajectory geometries in supercooled liquids.
- To identify and characterize distinct diffusion regimes.
- To link observed diffusion anomalies to potential-energy landscape features.
Main Methods:
- Molecular dynamics simulations of two distinct fragile glass-forming liquids.
- Statistical analysis of first-passage trajectory lengths.
- Examination of self-part of van Hove correlation function.
Main Results:
- Identified three distinct diffusion regimes: short-range confinement, persistent diffusion, and a novel long-range localization anomaly.
- The long-range localization is distinct from short-range cage confinement.
- Persistent diffusion correlates with exponential decay in the van Hove self-correlation function.
Conclusions:
- Particle trajectories in supercooled liquids exhibit complex multi-regime diffusion.
- The potential-energy landscape topography, with coalescing metabasins, explains the observed diffusion anomaly.
- This study provides a new perspective on diffusion dynamics in glass-forming systems.
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