Re-examination of the Fe{001}1×1-O structure

A recent first-principles total-energy calculation predicting a 23% expansion of the first Fe-Fe interlayer spacing in the Fe{001}1×1-O structure has led us to re-examine our 1977 LEED analysis of this structure, which had found a 7.7% expansion of that spacing. The new analysis is based on the same experimental data used in the early analysis, but expanded over an energy range almost twice as large; it tests parameter values reaching to and beyond the values predicted by the total-energy calculation; it takes into account possible multilayer relaxation of the Fe substrate and uses three reliability factors. The results discriminate strongly against the total-energy structure, and confirm and improve the 1977 structure. The interlayer distances are: 0.45 Å for O-Fe, 1.55 Å for the first and 1.47 Å for the second Fe-Fe layer (bulk value 1.43 Å), with an estimated accuracy of ±0.04 Å. © 1987.