A structural analysis of a caesium induced (1 x 2) reconstruction of Ag(110) (θCs ≈ 0.10ML) by low energy electron diffraction was presented. Evidence in favour of a topmost layer missing-row structure was found in agreement with an ion scattering study utilising channelling and blocking. The saw-tooth (Bonzel-Ferrer) model could be clearly excluded. Inclusion of the possibility of multilayer reconstruction particularly in the form of third layer buckling led to a small yet significant improvement in the R-factor. A second layer row pairing of 0.10Å (towards the top-layer “missing rows”) and a third layer bucking amplitude of 0.10Å were determined. The surface relaxations of the outermost three atomic layer spacings were modified to −11, −2 and −9% in comparison to the clean surface damped oscillatory relaxation of −7, + 1 and −2% respectively. Thus, the missing row model with multilayer relaxation/reconstruction favoured for the clean (110) surfaces of Au, Ir and Pt had conclusively been shown to extend to the alkali-induced reconstructions. However, the magnitude of the first layer contraction and third layer buckling were definitely smaller in the case of the alkali-induced (1 x 2) structure, yet still larger than theoretical predictions based on the embedded atom method.

The Surface Geometry of a Caesium Induced (1 x 2) Multilayer Reconstruction of Ag(110). C.J.Barnes, M.Lindroos, D.J.Holmes, D.A.King: Surface Science, 1989, 219[1-2], 143-60