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Density functional theories of surface interactions in salt solutions

Forsman, Jan LU (2009) In Journal of Chemical Physics 130(6).
Abstract
Most current density functional theories rely upon the presence of hard cores, also between ions of like charge. These hard cores should in principle reflect exchange repulsion. However, by the way in which these theories are formulated, the hard cores effectively determine the range of ion-ion correlations. This is because the mutual repulsion between like-charged ions is truncated below the corresponding hard sphere diameter. In most relevant applications, at least those related to ion correlations and surface forces in colloidal dispersions, exchange repulsion between like-charged ions is unimportant. This can easily be demonstrated by simulations. Unfortunately, the hard cores can in practice serve as fitting parameters in calculations... (More)
Most current density functional theories rely upon the presence of hard cores, also between ions of like charge. These hard cores should in principle reflect exchange repulsion. However, by the way in which these theories are formulated, the hard cores effectively determine the range of ion-ion correlations. This is because the mutual repulsion between like-charged ions is truncated below the corresponding hard sphere diameter. In most relevant applications, at least those related to ion correlations and surface forces in colloidal dispersions, exchange repulsion between like-charged ions is unimportant. This can easily be demonstrated by simulations. Unfortunately, the hard cores can in practice serve as fitting parameters in calculations with traditional density functional theory. In this work, we present alternative density functional theories to describe aqueous salt solutions. In these approaches, an approximation of the relevant "Coulomb hole" that results from correlations between like-charged ions is calculated for the system under study. Hence, our theories are completely free from fitting parameters, and the results are appropriately insensitive to the exchange repulsion acting between ions of like charge. The theories are evaluated by comparing predictions with simulation data, with an emphasis on ion correlations and surface interactions. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
statistical mechanics, liquid theory, density functional theory, adsorption, colloids
in
Journal of Chemical Physics
volume
130
issue
6
publisher
American Institute of Physics
external identifiers
  • wos:000263408800037
  • pmid:19222292
  • scopus:60349087007
ISSN
0021-9606
DOI
10.1063/1.3071195
language
English
LU publication?
yes
id
d128af45-03d5-4142-8a38-d1cff6535311 (old id 1372163)
date added to LUP
2009-05-08 13:25:49
date last changed
2017-01-01 04:49:07
@article{d128af45-03d5-4142-8a38-d1cff6535311,
  abstract     = {Most current density functional theories rely upon the presence of hard cores, also between ions of like charge. These hard cores should in principle reflect exchange repulsion. However, by the way in which these theories are formulated, the hard cores effectively determine the range of ion-ion correlations. This is because the mutual repulsion between like-charged ions is truncated below the corresponding hard sphere diameter. In most relevant applications, at least those related to ion correlations and surface forces in colloidal dispersions, exchange repulsion between like-charged ions is unimportant. This can easily be demonstrated by simulations. Unfortunately, the hard cores can in practice serve as fitting parameters in calculations with traditional density functional theory. In this work, we present alternative density functional theories to describe aqueous salt solutions. In these approaches, an approximation of the relevant "Coulomb hole" that results from correlations between like-charged ions is calculated for the system under study. Hence, our theories are completely free from fitting parameters, and the results are appropriately insensitive to the exchange repulsion acting between ions of like charge. The theories are evaluated by comparing predictions with simulation data, with an emphasis on ion correlations and surface interactions.},
  author       = {Forsman, Jan},
  issn         = {0021-9606},
  keyword      = {statistical mechanics,liquid theory,density functional theory,adsorption,colloids},
  language     = {eng},
  number       = {6},
  publisher    = {American Institute of Physics},
  series       = {Journal of Chemical Physics},
  title        = {Density functional theories of surface interactions in salt solutions},
  url          = {http://dx.doi.org/10.1063/1.3071195},
  volume       = {130},
  year         = {2009},
}