dc.contributor.author
Mamatkulov, Shavkat
dc.contributor.author
Fyta, Maria
dc.contributor.author
Netz, Roland R.
dc.date.accessioned
2018-06-08T03:54:36Z
dc.date.available
2014-03-13T09:01:36.749Z
dc.identifier.uri
https://refubium.fu-berlin.de/handle/fub188/16191
dc.identifier.uri
http://dx.doi.org/10.17169/refubium-20375
dc.description.abstract
We develop force field parameters for the divalent cations Mg2+, Ca2+, Sr2+,
and Ba2+ for molecular dynamics simulations with the simple point charge-
extended (SPC/E) water model. We follow an approach introduced recently for
the optimization of monovalent ions, based on the simultaneous optimization of
single ion and ion-pair properties.We consider the solvation free energy of
the divalent cations as the relevant single-ion property. As a probe for ion-
pair properties we compute the activity derivatives of the salt solutions. The
optimization of the ionic force fields is done in two consecutive steps.
First, the cation solvation free energy is determined as a function of the
Lennard-Jones (LJ) parameters. The peak in the ion-water radial distribution
function (RDF) is used as a check of the structural properties of the ions.
Second, the activity derivatives of the electrolytes MgY2, CaY2 , BaY2, SrY2
are determined through Kirkwood-Buff solution theory, where Y = Cl−, Br−, I−.
The activity derivatives are determined for the restricted set of LJ
parameters which reproduce the exact solvation free energy of the divalent
cations. The optimal ion parameters are those that match the experimental
activity data and therefore simultaneously reproduce single-ion and ion-pair
thermodynamic properties. For Ca2+, Ba2+, and Sr2+ such LJ parameters exist.
On the other hand, for Mg2+ the experimental activity derivatives can only be
reproduced if we generalize the combination rule for the anion-cation LJ
interaction and rescale the effective cation-anion LJ radius, which is a
modification that leaves the cation solvation free energy invariant. The
divalent cation force fields are transferable within acceptable accuracy,
meaning the same cation force field is valid for all halide ions Cl−, Br−, I−
tested in this study.
en
dc.rights.uri
http://publishing.aip.org/authors/web-posting-guidelines
dc.subject.ddc
500 Naturwissenschaften und Mathematik::530 Physik
dc.title
Force fields for divalent cations based on single-ion and ion-pair properties
dc.type
Wissenschaftlicher Artikel
dcterms.bibliographicCitation
The Journal of Chemical Physics. - 138 (2013), 2, Artikel Nr. 024505/1-12
dc.identifier.sepid
24508
dcterms.bibliographicCitation.doi
10.1063/1.4772808
dcterms.bibliographicCitation.url
http://dx.doi.org/10.1063/1.4772808
refubium.affiliation
Physik
de
refubium.mycore.fudocsId
FUDOCS_document_000000019875
refubium.note.author
Der Artikel wurde in einer Open-Access-Zeitschrift publiziert
refubium.resourceType.isindependentpub
no
refubium.mycore.derivateId
FUDOCS_derivate_000000003236
dcterms.accessRights.openaire
open access
dcterms.isPartOf.issn
00219606