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arXiv · 2609.29427

Diffusion of charged rods across 3D varying section channels

N. Ray·A. Semkiv·J. Harting·P. Malgaretti
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Abstract

We analyze the transport of rod-like particles by diffusion and drift in a three-dimensional channel with varying circular or elliptic cross section. Applying the Fick-Jacobs approximation to the transport equation of the particles' probability distribution, we derive an effective one-dimensional substitute model and the associated free energy profile. Our results show that the data for the mean first passage time of rods, once expressed as a function of the effective free energy barrier, collapse onto the same master curve as obtained for point or spherical particles. The observed universality provides a simple framework for predicting transport times of anisotropic particles in confined geometries without resolving the full multidimensional dynamics.

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N. Ray, A. Semkiv, J. Harting, P. Malgaretti. 2026-09-24. Diffusion of charged rods across 3D varying section channels. https://arxiv.org/abs/2609.29427

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