Anomalous diffusion in supercooled liquids: A long-range localizationin particle trajectories

• A statistical analysis of the geometries of particle trajectories in the supercooled liquid state isreported. The analysis we present here is based on the statistics of the first-passage trajectory length.We examine two structurally different fragile glass-forming liquids simulated by moleculardynamics. In both liquids, the trajectories are found to reveal three distinct diffusion regimes. Ashort-range confinement to the cage of nearest neighbors is followed by a persistent diffusionregime. At a still larger spatial scale, the particle trajectories demonstrate a novel diffusion anomaly:a long-range localization distinct from the short-range localization. This phenomenon can beinterpreted in terms of the potential-energy landscape topography with the local energy minimacoalescing into metabasins—compact domains with low escape probability. We also demonstratethat the persistent diffusion regime can be linked to the exponential decay of the self-part of thevan Hove correlation function.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

Anomalous diffusion; Diffusion regimes; Escape probability; Exponential decays; First-passage; Fragile glass; Local energy minima; Metabasins; Nearest neighbors; Particle trajectories; Potential energy landscapes; Range localization; Spatial scale; Statistical analysis; Supercooled liquid state; Supercooled liquids; Trajectory length; Van Hove correlation

Liquid physics

Vätskefysik

Defects and diffusion

Defekter och diffusion

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)