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Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
Order and disorder in the wetting layer on Ru(0001)
Mark Gallagher1, Ahmed Omer, George R Darling
1The University of Liverpool, Surface Science Research Centre, Oxford Street, Liverpool, UK.
Faraday Discussions
|February 21, 2009
Summary
Water forms an ordered O location but disordered layer on Ru(0001), revealed by low-energy electron diffraction (LEED) and He atom scattering (HAS). Density functional calculations explain this unique water monolayer structure.
Area of Science:
- Surface Science
- Physical Chemistry
- Materials Science
Background:
- Understanding water adsorption on metal surfaces is crucial for catalysis and materials science.
- Previous models often assumed an ice bilayer structure for water monolayers.
Purpose of the Study:
- To investigate the structural ordering of water monolayers on Ru(0001).
- To reconcile conflicting structural information from low-energy electron diffraction (LEED) and He atom scattering (HAS).
Main Methods:
- Low-energy electron diffraction (LEED) to probe O and Ru ordering.
- He atom scattering (HAS) to probe the top layer of O and H.
- Density functional calculations to model water monolayer structures.
Main Results:
- LEED indicated a commensurate (sqrt(3)xsqrt(3))R30° structure, suggesting ordering.
- HAS revealed a disordered water layer with low specular reflectivity.
- Density functional calculations proposed water chains with ordered O but disordered H orientation.
Conclusions:
- Water forms a unique monolayer structure on Ru(0001) with ordered oxygen but disordered proton orientation.
- This structural characteristic explains the differing results from LEED and HAS.
- The findings challenge the conventional ice bilayer model for water monolayers on metals.
