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Nature of the entropy versus self-diffusivity plot for simple liquids.
Charanbir Kaur1, Upendra Harbola, Shankar P Das
1School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India.
The Journal of Chemical Physics
|August 6, 2005
Summary
This study explores the link between liquid diffusion and excess entropy, finding a crossover in dynamics at intermediate densities. This crossover affects the Stokes-Einstein relation and diffusion coefficients.
Area of Science:
- Physical Chemistry
- Computational Fluid Dynamics
- Statistical Mechanics
Background:
- The empirical relation between self-diffusion coefficient (D(*)) and excess entropy (S) is a key area in liquid dynamics.
- Understanding diffusion in liquids is crucial for various chemical and physical processes.
Purpose of the Study:
- To investigate the empirical relation D(*) = a exp[S] using theoretical models.
- To analyze the role of interaction potentials and density on this relationship.
- To examine deviations from the Stokes-Einstein relation.
Main Methods:
- Theoretical model calculations.
- Analysis of self-diffusion coefficients and excess entropy.
- Examination of density-dependent phenomena and interaction potentials.
Main Results:
- Identified a crossover in the coefficient alpha at intermediate densities, indicating a shift in dynamics.
- Observed a departure from the Stokes-Einstein relation around this crossover density.
- Validated the entropy-diffusion relationship for scaled diffusion coefficients in binary mixtures.
Conclusions:
- The relationship between excess entropy and diffusion is complex and density-dependent.
- Cooperative dynamics significantly influence diffusion behavior in liquids.
- The findings offer insights into liquid transport properties and their theoretical underpinnings.