Previous low-energy electron diffraction and ion scattering measurements have shown that chemisorbed S on Ni(111) results in the reconstruction of the first Ni layer at coverages above 0.25ML. Soft X-ray photo-electron and high resolution electron energy loss spectroscopy data were presented that support two possible models for this reconstruction while eliminating several others. Soft X-ray photo-electron spectroscopy indicated that the S adsorbed in a single state at low coverages and in two different states at high coverages. High-resolution electron energy loss spectroscopy showed that the S-Ni coordination increased following reconstruction. The results were consistent with a reconstruction of the first Ni layer into a (100)-like surface with periodic gaps occurring after every four close-packed rows of Ni atoms in the [11¯2] direction. They were also consistent with a proposed modification of this model where the (100) terraces were altered by a “clock” reconstruction.

The Nature of the Sulfur Induced Surface Reconstruction on Ni(111). D.R.Mullins, D.R.Huntley, S.H.Overbury: Surface Science, 1995, 323[1-2], L287-92