On the effect of oxygen adsorption on the interlayer relaxation of the Zr(0001) surface

The oxygen adsorption on the Zr(0 0 0 1) surface is studied using first-pri nciples total-energy calculations. The calculations are performed in the fr amework of density-functional theory and pseudopotential theory. We compare results obtained with the LDA including generalized gradient corrections ( GGCs). We calculate the atomic structure and heat of adsorption for oxygen occupying various sites for coverage 1/4 less than or equal to Theta less t han or equal to 1. We find that the energetic hierarchy of the different ad sorption sites tested depend on non-local exchange-correlation effects. We also discuss the subsurface three domains model as proposed by Wang from LE ED analysis [Surf. Sci. 343 (1995) L1167]. At the end, relaxation of the zi rconium interlayer spacings is discussed as a function of the oxygen concen tration and in terms of GGCs. (C) 2001 Elsevier Science B.V. All lights res erved.