The adsorption geometry and chemical state of lysine on Cu{110}

► Lysine adsorbed on Cu{110} was studied by XPS and NEXAFS. ► At 300K, 70% of the molecules are in their zwitterionic state with no common molecular orientation. ► At 42OK a less densely packed layer is formed. ► Substrate bonds in the high-T phase involve the two O atoms and the two amino groups.