AVS 52nd International Symposium
    Surface Science Thursday Sessions
       Session SS1-ThM

Paper SS1-ThM3
Segregation of Anions at the Alkali Halide Solution/Vapor Interface Investigated by Photoemission Spectroscopy

Thursday, November 3, 2005, 9:00 am, Room 200

Session: Water-Surface Interactions
Presenter: H. Bluhm, Lawrence Berkeley National Laboratory
Authors: S. Ghosal, University of California, Irvine
H. Bluhm, Lawrence Berkeley National Laboratory
B.S. Mun, Lawrence Berkeley National Laboratory
G. Ketteler, Lawrence Berkeley National Laboratory
F.G. Requejo, Lawrence Berkeley National Laboratory
E.L.D. Hebenstreit, Lawrence Berkeley National Laboratory
D.F. Ogletree, Lawrence Berkeley National Laboratory
M. Salmeron, Lawrence Berkeley National Laboratory
J.C. Hemminger, University of California, Irvine
Correspondent: Click to Email
Ion-enhanced interactions with gases at aqueous solution interfaces may play an important role in the chemistry of concentrated inorganic solutions in the atmosphere. Using ambient pressure photoemission spectroscopy (PES) we have measured the concentration of ions at the surface of saturated potassium iodide and potassium bromide solutions. In the case of saturated potassium iodide solutions two iodine 4d peaks that are separated by a binding energy difference of 1.7 eV can be identified in the PES spectrum. Using photon-energy-dependent depth-profiling we have determined that the iodine peak with the higher binding energy is due to an iodine species at the solution interface, while the low binding energy peak is due to iodine from the bulk of the solution. The presence of an anion species at the solution interface is in agreement with our previous ambient pressure PES results that showed an enhancement of the halide anion concentration at the solution interface compared to the literature value for bulk solutions.@footnote 1@ @FootnoteText@ @footnote 1@S. Ghosal at al., Science 307, 563 (2005).