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CPP: Chemische Physik und Polymerphysik

CPP 13: Selforganized and supramolecular assemblies II

CPP 13.1: Vortrag

Montag, 7. März 2005, 11:15–11:30, TU C243

The interfacial structure of electrolyte solutions — •Thomas Krebs, Gunther Andersson, and Harald Morgner — Universität Leipzig, Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Linnéstrasse 2, 04103 Leipzig

The structure of the surface of salty liquid solutions plays an important role for reactions at the gas/liquid interface. Recently the question has been raised about the distribution of halide ions at liquid surfaces. MD Computer Simulations predict even segregation of the heavier halide ions to the surface in aqueous solution. This suggests a positive surface excess of the salt although the surface tension of the solution increases with salt concentration.

Neutral Impact Collision Ion Scattering Spectroscopy (NICISS) is a suitable method to determine concentration depth profiles of elements at liquid surfaces. We present data which show that halide ions can appear in the top layer of solutions in polar solvents. The topography around ions at the top surface layer can be evaluated. This is possible by applying NICISS in the angular resolved mode. Angle resolved measurements have been performed at solutions of Tetra-n-butylphosphonium bromide and potassium iodide in formamide and in glycerol.