Part of Focus on Advances in Surface and Interface Science 2009

 

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Abstract

Properties of the metal–water interface have been addressed by periodic density functional theory calculations, in particular with respect to the electronic and geometric structures of water bilayers on several transition metal surfaces. It will be demonstrated that the presence of the metal substrate leads to a significant polarization of the water bilayer. This causes a substantial water-induced reduction of the work function in spite of the weak water–metal interaction, but it is not associated with a significant change of the electronic structure of the metal substrates. The structure and the vibrational spectra of water bilayers at room temperatures have been studied performing ab initio molecular dynamics simulations. The simulations suggest that the water bilayer structure on noble metals is not stable at room temperature, whereas on more strongly interacting metal surfaces some ordering of the water layer persists. In addition, metal–water interfaces under electrochemical conditions, i.e. for charged metal substrates, are addressed. Our simulations show that the charging of the surface leads to characteristic changes in the wall–oxygen distribution and the vibrational spectra.

PACS

68.08.-p Liquid-solid interfaces

68.15.+e Liquid thin films

73.30.+y Surface double layers, Schottky barriers, and work functions

61.25.Em Molecular liquids

78.40.-q Absorption and reflection spectra: visible and ultraviolet

61.20.Ja Computer simulation of liquid structure

Subjects

Soft matter, liquids and polymers

Condensed matter: electrical, magnetic and optical

Surfaces, interfaces and thin films

Dates

Issue 12 (December 2009)

Received 2 April 2009

Published 11 December 2009