Hydroxyl on Stepped Copper and its Interaction with Water.

We describe the hydroxyl and mixed hydroxyl-water structures formed on a stepped copper surface following the reaction of adsorbed O with water at a low temperature and compare them to the structures found previously on plane copper surfaces. Thermal desorption profiles, STM, and low-energy electron diffraction show that water reacts with O at temperatures below 130 K on Cu(511). Two well-defined phases appear as the OH/HO layer is heated to desorb excess water, a 1OH:1HO phase and a pure OH phase.