Local environment of nitrate at the air-ice interface ...

• Main Author: Manoharan, Yanisha
• Format: Text
• Language: English
• Published: ETH Zurich 2023
• Subjects: air-ice interface; Nitrate; Hydrogen-bonding; Phase diagram; Eutectic; quasi-liquid layer QLL; Ice surface; N2O5; Actinometry; photolysis; Actinic flux; X-ray photoelectron spectroscopy XPS; Near-edge X-ray absorption fine structure NEXAFS; infoeu-repo/classification/ddc/540; Chemistry; Antarc*; Antarctic; Arctic
• Online Access: https://dx.doi.org/10.3929/ethz-b-000648617; http://hdl.handle.net/20.500.11850/648617

The topic of this thesis is the multiphase chemistry of nitric acid and nitrate in the cryosphere and the colder parts of the atmosphere. In Arctic and Antarctic snow or in ice particles of cirrus clouds in the upper troposphere, nitrate is one of the important ions. The photolysis of nitrate in ice of such particles or in snow can lead to the release of nitrogen oxides to the air in contact with it, which affects the hydroxyl radical budget and ozone production in the upper troposphere and snow covered remote and polar regions. The dissociation of acidic trace gases upon adsorption is deemed essential to explain their enhanced partitioning to ice as compared to non-acidic trace gases. More generally, reactions at interfaces of environmental relevance have a direct impact on the composition of the surrounding troposphere. Laboratory studies over the past decade have shown that photolysis of nitric acid or nitrate is enhanced at environmental interfaces. More specifically, the quantum yield of nitrate ...