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Explaining the T,V-dependent dynamics of glass forming liquids: The cooperative free volume model tested against new simulation results
Explaining the T,V-dependent dynamics of glass forming liquids: The cooperative free volume model tested against new simulation results
- Source :
- The Journal of Chemical Physics. 147:184503
- Publication Year :
- 2017
- Publisher :
- AIP Publishing, 2017.
-
Abstract
- In this article, we derive a rate model, the “cooperative free volume” (CFV) model, to explain relaxation dynamics in terms of a system’s free volume, Vfree, and its temperature, T, over widely varied pressure dependent conditions. In the CFV model, the rate a molecule moves a distance on the order of its own size is dependent on the cooperation of surrounding molecules to open up enough free space. To test CFV, we have generated extensive T,V dependent simulation data for structural relaxation times, τ, on a Kob and Andersen type Lennard-Jones (KA-LJ) fluid. The Vfree = V − Vhc values are obtained by estimating the limiting hard core volume, Vhc, through analysis of the KA-LJ PVT data. We provide the first simulation evidence that shows ln τ to be linearly proportional to 1/Vfree on isotherms, with T-dependent slopes, thus confirming our recent analysis of experimental systems. The linear relationship exhibited by the simulation data is further shown to occur at temperatures both above and below the tran...
- Subjects :
- Chemistry
General Physics and Astronomy
Thermodynamics
02 engineering and technology
Free space
Limiting
Pressure dependent
021001 nanoscience & nanotechnology
01 natural sciences
Hard core
Glass forming
Linear relationship
Lennard-Jones potential
0103 physical sciences
Physical and Theoretical Chemistry
010306 general physics
0210 nano-technology
Subjects
Details
- ISSN :
- 10897690 and 00219606
- Volume :
- 147
- Database :
- OpenAIRE
- Journal :
- The Journal of Chemical Physics
- Accession number :
- edsair.doi.dedup.....a2663b53e7fe52ba2a25efaaaa90f6d1
- Full Text :
- https://doi.org/10.1063/1.5001714