ION-BEAM CRYSTALLOGRAPHY OF CLEAN AND SULFUR COVERED NI(100)

Medium energy ion scattering has been used to determine the atomic structure of a Ni(110) surface covered with 0.5 monolayer of sulfur. After having confirmed that the sulfur atom resides in a fourfold-coordinated hollow site, it was found that its distance above the plane of the first Ni layer is 0.87 ± 0.03 Å. We measured a 6 ± 3% outward relaxation effect for the sulfur covered Ni(110) surface layer and an inward relaxation of 4 ± 1% when this surface is clean. © 1979.