Determination of an Adlayer Bonding Transition by Surface Extended X-Ray-Absorption Fine-Structure Spectroscopy: Cesium Adsorbed on Ag {111}

Abstract

As the Cs coverage of Ag{111} is increased from approximately 0.15 to 0.3 monolayer the Cs-Ag bond length is found to increase from 3.20 \ifmmode\pm\else\textpm\fi{} 0.03 to 3.50 \ifmmode\pm\else\textpm\fi{} 0.03 \AA{}. This dramatic change is associated with a transition in the cesium bonding from predominantly ionic at low coverage towards a more covalent state at high coverage.