Hydration of mineral surfaces probed at the molecular level.
By employing the nonlinear optical, interface selective experiment of sum frequency spectroscopy together with independent ab initio and density functional theory calculations, we determine the functional species of a corundum (001) surface: doubly coordinated OH groups which differ in their bond tilt angles. The interaction of the functional species with the adjacent water molecules is also observed. In a large pH range around the point of zero charge, the interaction is not controlled electrostatically but by hydrogen bonding. The functional species' tilt angles are crucial parameters, determining whether the species act as hydrogen bond donors or acceptors.
Flörsheimer
Mathias
M
Institute for Nuclear Waste Disposal, Research Centre Karlsruhe, Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany. florshg@ine.fzk.de
Kruse
Klaus
K
Polly
Robert
R
Abdelmonem
Ahmed
A
Schimmelpfennig
Bernd
B
Klenze
Reinhardt
R
Fanghänel
Thomas
T