Criegee intermediate-hydrogen sulfide chemistry at the air/water interface
Manoj Kumar1, Jie Zhong1, Joseph S Francisco1
1Department of Chemistry , University of Nebraska-Lincoln , Lincoln , Nebraska 68588 , USA . Email: xzeng1@unl.edu ;
Chemical Science
|October 4, 2017
Summary
The reaction between Criegee intermediates and hydrogen sulfide occurs rapidly at air/water interfaces, forming C-S bonds. This finding reveals a new non-photochemical pathway for atmospheric chemistry and H2S oxidation.
Area of Science:
- Atmospheric Chemistry
- Chemical Kinetics
- Computational Chemistry
Background:
- Criegee intermediates are key species in atmospheric oxidation processes.
- Hydrogen sulfide (H2S) is a significant atmospheric trace gas with various sources.
- Reactions at air/water interfaces play a crucial role in atmospheric chemistry.
Purpose of the Study:
- To investigate the reaction dynamics between the smallest Criegee intermediate (CH2OO) and hydrogen sulfide (H2S).
- To elucidate the reaction mechanisms and kinetics at the air/water interface.
- To explore the atmospheric implications of this reaction pathway.
Main Methods:
- Utilized Born-Oppenheimer molecular dynamic simulations.
- Focused on the air/water interface environment.
- Analyzed reaction pathways, including concerted and stepwise mechanisms.
Main Results:
- The reaction between CH2OO and H2S was observed to occur within picoseconds.
- Both concerted and stepwise mechanisms were identified, with the concerted pathway being dominant.
- The concerted reaction can proceed with or without the participation of water molecules.
Conclusions:
- The Criegee-H2S reaction offers a novel non-photochemical route for C-S bond formation in clouds.
- This reaction represents a potential new oxidation pathway for H2S in diverse terrestrial environments.
- The findings highlight the importance of interfacial reactions in atmospheric chemistry.
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