Overlayer structure determination by LEED at low energies: Na on Ni(001)

Analysis of new LEED data by Anderson (1975) shows that Na atoms in a c(2*2) overlap on Ni(001) sit in the four-fold hollows but, contrary to a previous analysis of Andersson and Pendry (see abstr. A28985) at a distance of 2.23+or-0.1AA from the surface. The sensitivity of the low-energy spectra to nonstructural features of the LEED model allows discrimination between different adsorbate potentials, inner potentials in the overlayer and surface barriers.