AN ION-SCATTERING STUDY OF THE SURFACE-STRUCTURE AND THERMAL VIBRATIONS ON IR(110)

The Ir(110) surface structure has been investigated in the temperature range from 300 to 1220 K. Ion scattering methods were used, i.e. surface channeling and neutral impact collision ion scattering spectroscopy (NICISS), to obtain information about the structural changes and the thermal vibrations of the surface atoms. Metastable (1 x 1) surfaces can be prepared by grazing incidence sputtering and by adsorption of O2, H2 and CO. Dependent of the pre-treatment the (1 x 1) structure converts into a (1 x 3) structure at temperatures between 540 and 850 K. In the (1 x 3) structure the r.m.s. amplitudes of the surface atoms are smaller than in the (1 x 1) structure.