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Hydrodynamic consideration of the finite size effect on the self-diffusion coefficient in a periodic rectangular
Gota Kikugawa1, Takeo Nakano2, Taku Ohara1
1Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
The Journal of Chemical Physics
|July 17, 2015
Summary
Molecular dynamics simulations reveal system size effects on liquid self-diffusion in rectangular boxes. Hydrodynamic theory accurately predicts these effects, showing a universal aspect ratio for infinite system diffusivity.
Area of Science:
- Computational physics
- Physical chemistry
Background:
- Previous studies showed anomalous diffusion in rectangular systems.
- Size effects on diffusion are well-understood in cubic systems via hydrodynamic interactions.
Purpose of the Study:
- Investigate system size effects on liquid self-diffusion in periodic rectangular parallelepipeds.
- Extend hydrodynamic theory to rectangular systems and validate with molecular dynamics (MD) simulations.
Main Methods:
- Employed molecular dynamics (MD) simulations.
- Extended hydrodynamic theory to periodic rectangular box systems.
- Compared theoretical predictions with MD simulation results.
Main Results:
- Hydrodynamic theory predictions showed good agreement with MD simulation results.
- Examined size effects in rod-shaped and film-type rectangular boxes.
- Identified a universal aspect ratio for infinite system diffusivity, independent of cross-sectional area or thickness.
Conclusions:
- Hydrodynamic theory successfully explains system size effects on diffusion in rectangular boxes.
- A simplified model was proposed for predicting size effects on diffusivity across practical aspect ratios.
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