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Beyond the dynamic density functional theory for steady currents: application to driven colloidal particles in a
P Tarazona1, Umberto Marini Bettolo Marconi
1Departamento de Física Teórica de la Materia Condensada, and Instituto de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
The Journal of Chemical Physics
|May 2, 2008
Summary
This study examines colloidal particle dynamics in narrow channels using a traveling potential. Results confirm prior work but reveal new phenomena like wakes and temperature inhomogeneity at high friction.
Area of Science:
- Statistical Mechanics
- Soft Matter Physics
- Computational Physics
Background:
- Recent interest in colloidal dynamics within confined geometries.
- Need to model particle inertia and phase-space distribution for accuracy.
- Limitations of existing Dynamic Density Functional Theory (DDFT) for certain conditions.
Purpose of the Study:
- Investigate steady-state properties of noninteracting colloidal particles in a traveling potential.
- Develop a theoretical framework accounting for particle inertia.
- Explore phenomena beyond DDFT, particularly at high friction.
Main Methods:
- Derivation of asymptotic solutions for the one-particle phase-space distribution using Hermite polynomials.
- Analysis of force and energy balance.
- Numerical computation of steady-state density and temperature profiles for an inverted parabolic potential.
Main Results:
- Rapid convergence of the Hermite polynomial expansion for high friction and low velocities.
- Confirmation of previous DDFT-based studies.
- Observation of a wake behind the potential and significant temperature field inhomogeneity at high friction.
Conclusions:
- The proposed model accurately describes colloidal dynamics, including inertial effects.
- The study highlights limitations of DDFT and reveals novel phenomena under specific conditions.
- Findings provide a more comprehensive understanding of colloidal behavior in driven systems.
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