Surface polarization strongly influences electrostatics in a nonlocal medium

Fuente: arXiv
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Auteurs principaux: Behjatian, Ali, Blossey, Ralf, Krishnan, Madhavi
Format: Preprint
Publié: 2024
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author Behjatian, Ali
Blossey, Ralf
Krishnan, Madhavi
author_facet Behjatian, Ali
Blossey, Ralf
Krishnan, Madhavi
contents Electrostatics in the solution phase is governed by free electrical charges such as ions, as well as by bound charges that arise when a polarizable medium responds to an applied field. In a local medium, described by a constant dielectric permittivity, the sign of the far-field electrostatic potential distribution around an object is governed by its electrical charge. We demonstrate significant departures from this expectation in a nonlocal medium characterized by a wave vector-dependent dielectric function. Here, surface polarization due to the solvent, or indeed non-solvent dipoles, may wield significant influence at large distances. The polarization correlation length may not only significantly augment the effective screening length, but we also show that the electrical contribution from polarization can compete with and even invert the sign of the electrical potential and the field arising from charge alone. These results hold ramifications for a range of apparently anomalous electrically governed observations such as underscreening, electrophoretic mobilities of charge-neutral objects, and long-ranged attraction between like-charged entities in water and other solvents.
format Preprint
id arxiv_https___arxiv_org_abs_2410_23920
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Surface polarization strongly influences electrostatics in a nonlocal medium
Behjatian, Ali
Blossey, Ralf
Krishnan, Madhavi
Soft Condensed Matter
Electrostatics in the solution phase is governed by free electrical charges such as ions, as well as by bound charges that arise when a polarizable medium responds to an applied field. In a local medium, described by a constant dielectric permittivity, the sign of the far-field electrostatic potential distribution around an object is governed by its electrical charge. We demonstrate significant departures from this expectation in a nonlocal medium characterized by a wave vector-dependent dielectric function. Here, surface polarization due to the solvent, or indeed non-solvent dipoles, may wield significant influence at large distances. The polarization correlation length may not only significantly augment the effective screening length, but we also show that the electrical contribution from polarization can compete with and even invert the sign of the electrical potential and the field arising from charge alone. These results hold ramifications for a range of apparently anomalous electrically governed observations such as underscreening, electrophoretic mobilities of charge-neutral objects, and long-ranged attraction between like-charged entities in water and other solvents.
title Surface polarization strongly influences electrostatics in a nonlocal medium
topic Soft Condensed Matter
url https://arxiv.org/abs/2410.23920