In this study, Auger electron spectroscopy and medium-energy ion scattering of 100-keV protons have been used to determine quantitatively the oxygen coverage during adsorption and the adsorbate-induced surface relaxation of the Fe(001)-(1×1)O structure at one monolayer oxygen coverage. The results show an outward relaxation of the first Fe-Fe layer spacing of 0.16±0.04 Å [(11.0±3.0)%], an outward relaxation of the second Fe-Fe interlayer spacing of 0.01±0.04 Å [(0.7±3.0)%], and a surface Debye temperature of 255 K. These results are consistent with low-energy electron diffraction studies but are in strong disagreement with the structure predicted by a recent first-principles total-energy calculation.

• Received 28 November 1988

DOI:https://doi.org/10.1103/PhysRevB.39.5713