Surface Extended Energy-Loss Fine Structures of Oxygen on Ni(100)

Surface electron-energy-loss fine structure above the oxygen K edge and the nickel M₂₃ edge has been investigated for several oxygen coverages on a Ni(100) system. In agreement with recent results, it is found that at low coverage the oxygen chemisorbs in the hollow position (0.85 ±{} 0.05 {} above the nickel plane). On increasing the coverage, islands of nickel oxide are formed. This technique for determining the local geometry of adsorbates is especially useful for light surface species like carbon, oxygen, and nitrogen.