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O: Fachverband Oberflächenphysik
O 28: Solid-Liquid Interfaces II: Structure and Spectroscopy
O 28.2: Talk
Tuesday, March 19, 2024, 10:45–11:00, H 1012
Surface stratification determines the interfacial water structure of simple electrolyte solutions — •Yair Litman1,2, Kuo-Yang Chiang2, Takakazu Seki2, Yuki Nagata2, and Mischa Bonn2 — 1Yusuf Hamied Department of Chemistry, University of Cambridge, U. K. — 2MPI for Polymer Research, Mainz, Germany.
For the past twenty years, the electrical-double layer (EDL) model has been the primary framework for analyzing
how ions behave at the interface between water and air and
interpreting various types of surface-selective experimental measurements. In this talk [1], I will present a combination
of surface-sensitive heterodyne-detected vibrational sum frequency generation (VSFG) and ab initio based molecular dynamics simulations to study the liquid/air interface of several aqueous electrolyte solutions. Our VSFG measurements highlight the shortcomings of the EDL model for a range of electrolytes, including but not restricted to NaCl, NaBr NaI, NaOH, and CsF aqueous solutions. We rationalize our findings by proposing a new microscopic picture in which
the surface of simple electrolyte solutions is stratified and
consists of an ion-depleted outer surface and an ion-enriched subsurface
layer, jointly determining the water interfacial structure.
[1] Y. Litman, K-Y. Chang, T. Seki, Y. Nagata, M. Bonn, submitted.
Keywords: Vibrational Spectroscopy; Ab initio molecular dynamics; Electrolytes