Condensed Matter Physics, 2016, vol. 19, No. 2, 23002
DOI:10.5488/CMP.19.23002           arXiv:1603.07106

Title: Ion clustering in aqueous salt solutions near the liquid/vapor interface
Author(s):
  J.D. Smith (Department of Chemistry, University of New Orleans, New Orleans, LA, 70148, USA) ,
  S.W. Rick (Department of Chemistry, University of New Orleans, New Orleans, LA, 70148, USA)

Molecular dynamics simulations of aqueous NaCl, KCl, NaI, and KI solutions are used to study the effects of salts on the properties of the liquid/vapor interface. The simulations use the models which include both charge transfer and polarization effects. Pairing and the formation of larger ion clusters occurs both in the bulk and surface region, with a decreased tendency to form larger clusters near the interface. An analysis of the roughness of the surface reveals that the chloride salts, which have less tendency to be near the surface, have a roughness that is less than pure water, while the iodide salts, which have a greater surface affinity, have a larger roughness. This suggests that ions away from the surface and ions near the surface affect the interface in opposite ways.

Key words: interface, charge transfer, ion pairing, aqueous ions
PACS: 05.20.-y, 82.20.Wt, 83.10.Rs, 68.03.Hj


Full text [pdf] << List of papers