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Ions confined in spherical dielectric cavities modeled by a splitting field-theory.

Lue, Leo and Linse, Per LU (2015) In Journal of Chemical Physics 142(14).
Abstract
The properties of ions confined within spherical dielectric cavities are examined by a splitting field-theory and Monte Carlo simulations. Three types of cavities are considered: one possessing a uniform surface charge density, one with a uniform volume charge density, and one containing mobile ions. In all cases, mobile counterions are present within the dielectric sphere. The splitting theory is based on dividing the electrostatic interaction into long- and short-wavelength contributions and applying different approximations on the two contributions. The splitting theory works well for the case where the dielectric constant of the confining sphere is equal to or less than that of the medium external to the sphere. Nevertheless, by... (More)
The properties of ions confined within spherical dielectric cavities are examined by a splitting field-theory and Monte Carlo simulations. Three types of cavities are considered: one possessing a uniform surface charge density, one with a uniform volume charge density, and one containing mobile ions. In all cases, mobile counterions are present within the dielectric sphere. The splitting theory is based on dividing the electrostatic interaction into long- and short-wavelength contributions and applying different approximations on the two contributions. The splitting theory works well for the case where the dielectric constant of the confining sphere is equal to or less than that of the medium external to the sphere. Nevertheless, by extending the theory with a virial expansion, the predictions are improved. However, when the dielectric constant of the confining sphere is greater than that of the medium outside the sphere, the splitting theory performs poorly, only qualitatively agreeing with the simulation data. In this case, the strong-coupling expansion does not seem to work well, and a modified mean-field theory where the counterions interact directly with only their own image charge gives improved predictions. The splitting theory works best for the system with a uniform surface charge density and worst for the system with a uniform volume charge density. Increasing the number of ions within the sphere, at a fixed radius, tends to increase the ion density near the surface of the sphere and leads to a depletion region in the sphere interior; however, varying the ion number does not lead to any qualitative changes in the performance of the splitting theory. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
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in
Journal of Chemical Physics
volume
142
issue
14
publisher
American Institute of Physics
external identifiers
  • pmid:25877592
  • scopus:84928494392
  • wos:000352969600039
ISSN
0021-9606
DOI
10.1063/1.4917256
language
English
LU publication?
yes
id
de0ec944-fd80-4dca-b8de-9961cd110f5f (old id 5341770)
date added to LUP
2015-05-22 15:18:02
date last changed
2017-01-01 03:32:22
@article{de0ec944-fd80-4dca-b8de-9961cd110f5f,
  abstract     = {The properties of ions confined within spherical dielectric cavities are examined by a splitting field-theory and Monte Carlo simulations. Three types of cavities are considered: one possessing a uniform surface charge density, one with a uniform volume charge density, and one containing mobile ions. In all cases, mobile counterions are present within the dielectric sphere. The splitting theory is based on dividing the electrostatic interaction into long- and short-wavelength contributions and applying different approximations on the two contributions. The splitting theory works well for the case where the dielectric constant of the confining sphere is equal to or less than that of the medium external to the sphere. Nevertheless, by extending the theory with a virial expansion, the predictions are improved. However, when the dielectric constant of the confining sphere is greater than that of the medium outside the sphere, the splitting theory performs poorly, only qualitatively agreeing with the simulation data. In this case, the strong-coupling expansion does not seem to work well, and a modified mean-field theory where the counterions interact directly with only their own image charge gives improved predictions. The splitting theory works best for the system with a uniform surface charge density and worst for the system with a uniform volume charge density. Increasing the number of ions within the sphere, at a fixed radius, tends to increase the ion density near the surface of the sphere and leads to a depletion region in the sphere interior; however, varying the ion number does not lead to any qualitative changes in the performance of the splitting theory.},
  articleno    = {144902},
  author       = {Lue, Leo and Linse, Per},
  issn         = {0021-9606},
  language     = {eng},
  number       = {14},
  publisher    = {American Institute of Physics},
  series       = {Journal of Chemical Physics},
  title        = {Ions confined in spherical dielectric cavities modeled by a splitting field-theory.},
  url          = {http://dx.doi.org/10.1063/1.4917256},
  volume       = {142},
  year         = {2015},
}