Local hydroxyl adsorption geometry on TiO2(110)

Abstract

The local structure of the hydroxyl species on the rutile TiO${}_{2}$(110) surface has been determined both experimentally and computationally. The experimental study exploited chemical state--specific O 1s scanned-energy mode photoelectron diffraction from a surface exposed to atomic hydrogen, while density functional theory calculations were used to provide complementary information. As expected on the basis of previous studies, the bridging O atoms of the clean surface are hydroxylated, but this causes surprisingly small changes in the surrounding surface relaxation. Experiment and theory are in good agreement regarding the magnitude of these atomic movements. Specifically, the Ti-O${}_{\mathrm{OH}}$ surface bond is significantly longer (by 0.10--0.15 \AA{}) than that of Ti-O${}_{\mathrm{bridging}}$ bonds on the clean surface.