Multiscale Modeling of Ion Transport in Nanopores: Fitting Implicit-Water Radial Diffusion Profiles to Explicit-Water Molecular Dynamics
Abstract
We develop a multiscale approach for incorporating molecular-scale transport information into computationally efficient models of ion transport through nanopores. A radially varying effective diffusion coefficient profile is fitted to radial conductivity profiles obtained from explicit-water molecular dynamics (MD) simulations. The fitting is performed within the NP+LEMC framework, which combines the Nernst--Planck equation with Local Equilibrium Monte Carlo to account for ion correlations beyond mean-field approximation. We apply the approach to NaCl, CaCl2, and their mixtures in a negatively charged silica nanopore. The resulting diffusion coefficient profiles reproduce the radial current distributions of the MD simulations, including the strong suppression of ionic mobility near the pore wall that cannot be captured by a spatially constant diffusion coefficient inside the pore. NaCl and CaCl2 exhibit qualitatively different transport behavior: the former is cation selective due to enhanced near-wall Na+ conduction, whereas the latter shows weak anion selectivity because strongly bound Ca2+ ions have strongly suppressed mobility near the surface. For NaCl--CaCl2 mixtures, preferential Ca2+ binding leads to nonlinear changes in ionic conductance. The approach establishes a bridge between experimentally relevant device behavior and computationally efficient reduced models, with explicit-water MD providing the molecular-scale information that can be incorporated into the effective transport coefficients.
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BibTeX
@misc{valisko2026multiscale,
title = {{Multiscale Modeling of Ion Transport in Nanopores: Fitting Implicit-Water Radial Diffusion Profiles to Explicit-Water Molecular Dynamics}},
author = {Mónika Valiskó and Salman Shabbir and Eszter Molnárné Lakics and Zoltán Ható and Dezső Boda},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.23575},
eprint = {2609.23575},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.23575},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Multiscale Modeling of Ion Transport in Nanopores: Fitting Implicit-Water Radial Diffusion Profiles to Explicit-Water Molecular Dynamics
AU - Mónika Valiskó
AU - Salman Shabbir
AU - Eszter Molnárné Lakics
AU - Zoltán Ható
AU - Dezső Boda
PY - 2026
DA - 2026/09/20
PB - arXiv
DO - 10.48550/arxiv.2609.23575
UR - https://arxiv.org/abs/2609.23575
AB - We develop a multiscale approach for incorporating molecular-scale transport information into computationally efficient models of ion transport through nanopores. A radially varying effective diffusion coefficient profile is fitted to radial conductivity profiles obtained from explicit-water molecular dynamics (MD) simulations. The fitting is performed within the NP+LEMC framework, which combines the Nernst--Planck equation with Local Equilibrium Monte Carlo to account for ion correlations beyond mean-field approximation. We apply the approach to NaCl, CaCl_2, and their mixtures in a negatively charged silica nanopore. The resulting diffusion coefficient profiles reproduce the radial current distributions of the MD simulations, including the strong suppression of ionic mobility near the pore wall that cannot be captured by a spatially constant diffusion coefficient inside the pore. NaCl and CaCl_2 exhibit qualitatively different transport behavior: the former is cation selective due to enhanced near-wall Na^+ conduction, whereas the latter shows weak anion selectivity because strongly bound Ca^2+ ions have strongly suppressed mobility near the surface. For NaCl--CaCl_2 mixtures, preferential Ca^2+ binding leads to nonlinear changes in ionic conductance. The approach establishes a bridge between experimentally relevant device behavior and computationally efficient reduced models, with explicit-water MD providing the molecular-scale information that can be incorporated into the effective transport coefficients.
ER -