Molecular Physics seminar

The Role of Organics in the Chemical Composition and Reactivity at the Surface of Halide Solutions Relevant for Marine Aerosol or Ocean Surface Water

by Ming-Tao Lee (Fysikum / Chemical Physics)

FA31 ()


Oceans cover approximately 71% of the Earth's surface and are playing a key role in climate regulation via a large number of physical and chemical processes. Seawater constitutes a complex aqueous electrolyte with an average salt concentration of 0.5 molar, the dominant ionic solutes being Na+ and Cl- (followed by Mg2+, SO4-, Br-, and I- to mention a few). While present in much lower concentrations, organic materials are highly important in affecting the surface-specific chemistry of sea-water aqueous systems, given their high surface propensity. The overall aim of the present project was to develop a detailed insight into the behavior of sodium halide species at mixed organic/aqueous liquid surfaces. Specific goals include: Firstly, laboratory experiments related to the structure and heterogeneous reactivity of aqueous halide solutions in the context of atmospheric chemistry in marine environments and further investigations on how such surface reactions are affected by the presence of various relevant organic compounds. Secondly, establishing an understanding of the interplay of sodium halide ions and organic solutes at the air-water interface at a molecular level. The primary approach to achieve these goals were performing synchrotron-based studies using near-ambient pressure X-ray photoelectron spectroscopy, at the Swiss Light Source.