Charge transfer at air-water interfaces: A machine learning potential-based molecular dynamics study.
Zhiwei Wang1, Zhaoan Chen1, Junjie Fang1
1Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
The Journal of Chemical Physics
|June 25, 2025
Summary
Water molecules at air-water interfaces exhibit uneven charge distribution due to hydrogen bonding. This finding offers atomic-level insights into interfacial water
Area of Science:
- Physical Chemistry
- Computational Chemistry
- Materials Science
Background:
- Water's interfacial behavior is critical in natural and industrial processes.
- Understanding hydrogen bonding and charge transfer at water interfaces is limited.
Purpose of the Study:
- To investigate the structure and charge transfer characteristics of water at air-water interfaces.
- To elucidate the relationship between hydrogen bonding and charge distribution.
Main Methods:
- Development of machine learning potentials with near density functional theory (DFT) accuracy.
- Utilizing datasets from ab initio molecular dynamics simulations.
- Exploration of interfacial water structure and charge transfer.
Main Results:
- Revealed non-uniform charge distribution at the air-water interface.
- Outermost water molecules (air-contacting) are positively charged.
- Sub-interface water molecules are negatively charged, driven by H-bond asymmetry.
Conclusions:
- Atomic-level insights into charge transfer mechanisms of interfacial water.
- Demonstrated the role of hydrogen bond donor-acceptor asymmetry in interfacial charge.
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