Core-Level Binding Energy Reveals Hydrogen Bonding Configurations of Water Adsorbed on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>TiO</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:mo stretchy="false">(</mml:mo><mml:mn>110</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math> Surface
C. Kamal, Nader Stenberg, L. E. Walle, D. Ragazzon, A. Borg, P. Uvdal, Natalia V. Skorodumova, Michael Odelius, A. Sandell
Abstract
Using x-ray photoelectron spectroscopy of the oxygen $1s$ core level, the ratio between intact (${\mathrm{D}}_{2}\mathrm{O}$) and dissociated (OD) water in the hydrated stoichiometric ${\mathrm{TiO}}_{2}(110)$ surface is determined at varying coverage and temperature. In the submonolayer regime, both the ${\mathrm{D}}_{2}\mathrm{O}\ensuremath{\mathbin:}\mathrm{OD}$ ratio and the core-level binding energy of ${\mathrm{D}}_{2}\mathrm{O}$ ($\mathrm{\ensuremath{\Delta}}\mathrm{BE}$) decrease with temperature. The observed variations in $\mathrm{\ensuremath{\Delta}}\mathrm{BE}$ are shown with density functional theory to be governed crucially and solely by the local hydrogen bonding environment, revealing a generally applicable classification and details about adsorption motifs.