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Fokker-Planck analysis of separation dependent potentials and diffusion coefficients in simulated microscopy
Daniel J Beltran-Villegas1, Ray M Sehgal, Dimitrios Maroudas
1Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.
The Journal of Chemical Physics
|February 2, 2010
Summary
A new Fokker-Planck (FP) analysis method for total internal reflection microscopy (TIRM) and video microscopy (VM) allows simultaneous extraction of colloidal interaction potentials and diffusion coefficients. This approach enhances the study of particle dynamics near surfaces.
Area of Science:
- Colloid and Surface Science
- Soft Matter Physics
- Microscopy Techniques
Background:
- Total internal reflection microscopy (TIRM) and video microscopy (VM) are established techniques for studying colloidal interactions.
- Current analysis methods primarily yield particle-surface potentials and average diffusion coefficients.
- Limitations exist in extracting dynamic information and complex interactions.
Purpose of the Study:
- To develop a novel Fokker-Planck (FP) formalism for enhanced analysis of TIRM and VM data.
- To enable simultaneous extraction of particle-surface interaction potentials and position-dependent diffusion coefficients.
- To explore capabilities for measuring hydrodynamic interactions and nonequilibrium states.
Main Methods:
- Development of a Fokker-Planck (FP) formalism.
- Application of the FP analysis to Brownian dynamics simulations of single-particle TIRM and VM experiments.
- Exploration of spatial and temporal sampling effects on force interpretation.
Main Results:
- The FP formalism successfully extracts both static (potentials) and dynamic (diffusion) information.
- Demonstrated ability to measure separation-dependent hydrodynamic interactions.
- Identified applicability across various experimental configurations and sampling parameters.
Conclusions:
- The developed FP analysis provides a powerful tool for detailed characterization of colloidal systems near surfaces.
- Offers significant advantages over existing methods for studying complex particle dynamics.
- Lays the groundwork for investigating particle ensembles and nonequilibrium phenomena.
