title: Hydration of mineral surfaces probed at the molecular level.
abstract: 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.
authors.affiliation: Institute for Nuclear Waste Disposal, Research Centre Karlsruhe, Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany. florshg@ine.fzk.de
authors.forename: Mathias
authors.initials: M
authors.lastname: Flörsheimer
authors.forename: Klaus
authors.initials: K
authors.lastname: Kruse
authors.forename: Robert
authors.initials: R
authors.lastname: Polly
authors.forename: Ahmed
authors.initials: A
authors.lastname: Abdelmonem
authors.forename: Bernd
authors.initials: B
authors.lastname: Schimmelpfennig
authors.forename: Reinhardt
authors.initials: R
authors.lastname: Klenze
authors.forename: Thomas
authors.initials: T
authors.lastname: Fanghänel