A low-energy electron diffraction structure analysis was performed for the W(100) c(2 x 2) surface reconstruction. Models with pure vertical displacements of the surface atoms could be clearly ruled out while others with predominant lateral displacements in the (11) and (01) directions result in a very good agreement with the experimental curves. However, a clear discrimination between these models was prevented by the insensitivity of normal incidence spectra to the direction of atomic displacements parallel to the surface. A minimum Pendry r-factor of r=0.26 was achieved for a refined model suggested by Debe and King (1979) with a multilayer relaxation (first inter-layer spacing d12 = 1.47Å second inter-layer spacing d23=1.60Å, and a reconstruction in the first and second layer with lateral displacements in the (11) direction (first layer: 0.24Å; second layer: 0.02Å).

LEED Intensity Analysis of the Clean W(100) c(2 x 2) Surface Reconstruction. H.Landskron, N.Bickel, K.Heinz, G.Schmidtlein, K.Muller: Journal of Physics - Condensed Matter, 1989, 1, 1-12