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Specific Cation Effects on SCN in Bulk Solution and at the Air−Water Interface

Tesei, Giulio LU ; Aspelin, Vidar LU and Lund, Mikael LU (2018) In The Journal of Physical Chemistry Part B 122(19). p.5094-5105
Abstract
The large and sparsely hydrated thiocyanate anion, SCN–, plays a prominent role in the study of specific ion effects in biological, colloid, and atmospheric chemistry due to its extreme position in the Hofmeister series. Using atomistic modeling of aqueous SCN– solutions, we provide novel insight at the molecular scale into the experimentally observed differences in ion pairing, clustering, reorientation dynamics, mutual diffusion, and solubility between the sodium, Na+, and the potassium, K+, salt. Compared to KSCN, NaSCN has a less pronounced tendency to ion pairing; nevertheless, at high salt concentrations, we observe a strong attraction between Na+ cations and the nitrogen end of SCN–, resulting in larger and more closely packed ion... (More)
The large and sparsely hydrated thiocyanate anion, SCN–, plays a prominent role in the study of specific ion effects in biological, colloid, and atmospheric chemistry due to its extreme position in the Hofmeister series. Using atomistic modeling of aqueous SCN– solutions, we provide novel insight at the molecular scale into the experimentally observed differences in ion pairing, clustering, reorientation dynamics, mutual diffusion, and solubility between the sodium, Na+, and the potassium, K+, salt. Compared to KSCN, NaSCN has a less pronounced tendency to ion pairing; nevertheless, at high salt concentrations, we observe a strong attraction between Na+ cations and the nitrogen end of SCN–, resulting in larger and more closely packed ion clusters. To accurately model aqueous SCN– solutions in computer simulations, we develop a thermodynamically consistent force field rooted in quantum-chemical calculations and refined using the Kirkwood–Buff theory. The force field is compatible with the extended simple point charge and three-point optimal point charge classical water models and reproduces experimental activity derivatives and air–water surface tension for a wide range of salt concentrations. (Less)
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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
122
issue
19
pages
5094 - 5105
publisher
The American Chemical Society (ACS)
external identifiers
  • pmid:29671594
  • scopus:85046345121
ISSN
1520-5207
DOI
10.1021/acs.jpcb.8b02303
project
Interactions in aqueous salt solutions: Atomistic modelling versus experiment
language
English
LU publication?
yes
id
63baf340-831b-49a7-8322-9345512852e0
date added to LUP
2018-08-21 14:20:48
date last changed
2021-03-24 05:50:16
@article{63baf340-831b-49a7-8322-9345512852e0,
  abstract     = {The large and sparsely hydrated thiocyanate anion, SCN–, plays a prominent role in the study of specific ion effects in biological, colloid, and atmospheric chemistry due to its extreme position in the Hofmeister series. Using atomistic modeling of aqueous SCN– solutions, we provide novel insight at the molecular scale into the experimentally observed differences in ion pairing, clustering, reorientation dynamics, mutual diffusion, and solubility between the sodium, Na+, and the potassium, K+, salt. Compared to KSCN, NaSCN has a less pronounced tendency to ion pairing; nevertheless, at high salt concentrations, we observe a strong attraction between Na+ cations and the nitrogen end of SCN–, resulting in larger and more closely packed ion clusters. To accurately model aqueous SCN– solutions in computer simulations, we develop a thermodynamically consistent force field rooted in quantum-chemical calculations and refined using the Kirkwood–Buff theory. The force field is compatible with the extended simple point charge and three-point optimal point charge classical water models and reproduces experimental activity derivatives and air–water surface tension for a wide range of salt concentrations.},
  author       = {Tesei, Giulio and Aspelin, Vidar and Lund, Mikael},
  issn         = {1520-5207},
  language     = {eng},
  month        = {04},
  number       = {19},
  pages        = {5094--5105},
  publisher    = {The American Chemical Society (ACS)},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Specific Cation Effects on SCN<sup>–</sup> in Bulk Solution and at the Air−Water Interface},
  url          = {http://dx.doi.org/10.1021/acs.jpcb.8b02303},
  doi          = {10.1021/acs.jpcb.8b02303},
  volume       = {122},
  year         = {2018},
}