O(2X1)-AG(110) MISSING-ROW RECONSTRUCTION - STRUCTURE DETERMINATION BY LOW-ENERGY ION-SCATTERING

Impact collision ion scattering spectroscopy using Ne+ has been employed to determine the structure of the O(2 X 1)-Ag(110) phase. The analysis of experimental data by Monte Carlo simulation of the ion trajectories confirms the missing-row reconstruction with the formation of -Ag-O-Ag- chains (added rows) along the [001] direction. Oxygen is found to occupy the long-bridge site 0.03+/-0.08 angstrom below the silver atoms, while the first-to-second and the second-to-third interlayer spacings are 1.66+/-0.03 angstrom and 1.32+/-0.03 angstrom, respectively. A lateral displacement (0.08+/-0.03 angstrom) of the second-layer Ag atoms towards the missing rows is observed in addition to a vertical buckling in the third layer: the atoms lying under the missing rows are held about 0.08 angstrom above those positioned under the added rows.