Abstract :
Adsorption of oxygen on crystalline nickel surface produces sequence of diffraction patterns shown in upper row. These patterns can be accounted for by the surface atom arrangements. As oxygen atom concentration increases, streaks appear, implying random oxygen positions. At 1/2 oxygen coverage, surface is ordered and streaks have coalesced into sharp spots halfway between original spots. At 2/3 oxygen coverage a triply periodic pattern and atomic arrangement occur.
