Normal photoelectron diffraction of O/Cu(001): A surface-structural determination

The two systems c(2×2)O/Cu(001) and (2×22) R 45° O/Cu(001) have been studied by normal photoelectron diffraction (NPD), with the use of O(1s) line. In the c(2×2) structure oxygen occupies the fourfold hollow site, with d_⊥=0.80(5) Å. The 2×22 structure has a similar NPD curve, indicating the same local site geometry for the c(2×2) sublattice.