Surface crystallography of the c(2×2) sodium overlayer on Al(100)

Experimental LEED intensity-energy spectra are reported for clean Al(100) and for c(2×2) Na on Al(100). The experimental results are compared with spectra calculated with the layer-KKR method and found to be in good agreement for both the clean surface and the overiayer. For the overlayer, the best agreement is obtained for Na atoms in the four-fold hollow site at a perpendicular distance of 2.05 ± 0.1 Å. © 1976.