Structure and interactions at the Mg(0001)/water interface: An ab initio study.

Area of Science:

• Materials Science
• Physical Chemistry
• Surface Science

Background:

• Understanding metal/water interfaces is critical for processes like aqueous corrosion.
• Experimental investigation of these buried interfaces is challenging, necessitating computational approaches.

Purpose of the Study:

• To elucidate the molecular structure of the Mg(0001)/water interface.
• To investigate atomic interactions and electronic structure at the interface.
• To provide insights into the initial stages of aqueous magnesium corrosion.

Main Methods:

• Employed second-generation Car-Parrinello molecular dynamics (MD) for structural analysis.
• Utilized static density functional theory (DFT) calculations for atomic interactions and electronic properties.
• Performed detailed structural analyses of both metal surface atoms and near-surface water molecules.

Main Results:

• Water adsorption induces significant surface roughening of the Mg(0001) surface.
• Strongly adsorbed water covers approximately 1/4 of available surface sites.
• Adsorbed water molecules tend to avoid clustering due to Coulombic repulsion.

Conclusions:

• The Mg(0001)/water interface exhibits unique characteristics, including high surface distortion and a small difference between the metal work function and the metal/water potential of zero charge.
• The findings offer crucial structural information for understanding aqueous magnesium corrosion.
• The study provides generalizable insights into the driving forces governing metal/water interface structures.