The structure of the (√3 × √3 )R30° overlayer formed by coadsorption of Cs and O atoms (${\mathrm{\theta }}_{\mathrm{Cs}}$=${\mathrm{\theta }}_0$=0.33) on a Ru(0001) surface was determined by low-energy electron diffraction. Both adsorbates occupy hcp-type hollow sites. If compared with the structures of the respective pure adsorbate phases, the bond lengths are modified in a way consistent with an effective transfer of electronic charge from Cs to O.

• Received 22 June 1992

DOI:https://doi.org/10.1103/PhysRevB.46.4360