Ion depletion near a solution surface: is image-charge repulsion sufficient?
Grazing-incidence Rutherford backscattering and angle-resolved x-ray photoelectron spectrometry are used to determine the ion-concentration profiles near the surface of a solution consisting of a salt (TEABr) in a weakly polar organic liquid (polyethylene glycol) with atomic-layer depth resolution. The predictions of a model, in which ions in solution are repelled from the surface due to a screened Coulomb interaction with their image charge, are in good agreement with measured ion profiles. This contrasts with the behavior of salts in aqueous and highly polar organic solutions.
Institute for Atmospheric and Climate Science, ETH Zurich, 8092 Zurich, Switzerland.
Ulrich K
UK
Krieger
Institute for Atmospheric and Climate Science, ETH Zurich, 8092 Zurich, Switzerland.
Maurus
M
Hess
Institute for Atmospheric and Climate Science, ETH Zurich, 8092 Zurich, Switzerland.
Thomas
T
Peter
Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland and Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, 09042 Monserrato (Cagliari), Italy.
Antonella
A
Rossi
Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland.
Nicholas D
ND
Spencer
Physics Department, University at Albany, Albany, New York 12222, USA.
William A
WA
Lanford