Structure of TiO2 rutile (110) (1 x 1) from ion scattering measurements

9.22 keV oxygen ion scattering has been used to examine the (110) surface structure of TiO2. rutile. Peaks in the spectrum of the emitted ions at 45 degrees and at 77 degrees are found at the energies expected for O+-Ti and O+-O collisions by surface atoms. Surface preoparation to optimize the 1 x 1 structure involved annealing a previously sputtered surface to 600 degrees C, first in 10(-6) Torr of O-2, and then in UHV. Azimuthal and elevation angular variations of the yields for low incidence angles show shadowing effects. Preliminary analysis seems to be consistent with the (1 x 1) model of a complete surface layer, with rows of oxygen atoms above on the titanium bridge sites. The data suggests that our sample preparation produces incomplete rows of above-surface oxygen atoms, or frequent steps.