The behaviour of the NiO(111) surface has been investigated by grazing inci
dence X-ray scattering (GIXS). We show on single crystals with an improved
crystalline quality that NiO(111) is always p(2 x 2) reconstructed. After a
ir annealing the structure is close to the predicted octopolar reconstructi
on; after in situ annealing and oxidation it is very different. The transfo
rmation of the surface is continuous with temperature but seems to be only
based on two possible atomic configurations. (C) 1999 Elsevier Science B.V.
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