guest ::
| Home > Publications database > Heterogeneous diffusion, viscosity, and the Stokes-Einstein relation in binary liquids |
| Home > Publications database > Heterogeneous diffusion, viscosity, and the Stokes-Einstein relation in binary liquids |
| Journal Article | FZJ-2016-02533 |
;
2016
APS
College Park, Md.
This record in other databases: 
Please use a persistent id in citations: http://hdl.handle.net/2128/11192 doi:10.1103/PhysRevE.93.052607
Abstract: We investigate the origin of the breakdown of the Stokes-Einstein relation (SER) between diffusivity and viscosity in undercooled melts. A binary Lennard-Jones system, as a model for a metallic melt, is studied by molecular dynamics. A weak breakdown at high temperatures can be understood from the collectivization of motion, seen in the isotope effect. The strong breakdown at lower temperatures is connected to an increase in dynamic heterogeneity. On relevant time scales some particles diffuse much faster than the average or than predicted by the SER. The van Hove self-correlation function allows one to unambiguously identify slow particles. Their diffusivity is even less than predicted by the SER. The time span of these particles being slow particles, before their first conversion to be a fast one, is larger than the decay time of the stress correlation. The contribution of the slow particles to the viscosity rises rapidly upon cooling. Not only the diffusion but also the viscosity shows a dynamically heterogeneous scenario. We can define a “slow” viscosity. The SER is recovered as the relation between slow diffusivity and slow viscosity.
; 
; 
; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; Nationallizenz
; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection
|
The record appears in these collections: |
PDF
PDF (PDFA)