RELAXATIONS IN THE MISSING-ROW STRUCTURE OF THE (1X2) RECONSTRUCTED SURFACES OF AU(110) AND PT(110)

The atomic structure of the (1 × 2) reconstructed (110) surfaces of Au and Pt has been investigated in detail using X-ray diffraction. For both surfaces the reconstruction involves several layers of atoms. The top layer spacing is contracted and pairing occurs in the second and fourth layers. There have been enough investigations of these surfaces with other experimental methods that a detailed comparison can now be made. Though there is full agreement on the missing-row model, this is not true for the magnitude of the relaxations occurring at the surfaces. In general the X-ray diffraction results compare better with electron diffraction data than with ion scattering experiments. Many theoretical approaches fail to predict the correct sign and/or magnitude of some of the relaxations. © 1990.