OXYGEN-INDUCED RECONSTRUCTION OF RH(110) AND (113) SINGLE-CRYSTAL PLANES

The interaction of oxygen with Rh field emitter surfaces has been inve stigated by means of field ion microscopy (FIM). It has been found tha t the field-free exposure of 20 L (1 L = 1.3 x 10(-4) Pa . s) oxygen t o samples at temperatures between 400 and 500 K leads to the reconstru ction of individual surface planes. In particular, the stepped Rh{110} and {113} surface planes exhibit ''missing-row'' or (n x 2) and (n x 3) facet structures, whereby n = 1, 2. These structural changes are th ermally activated and do not occur at temperatures below 400 K. Stable micrographs with insignificant species desorption during Ne imaging h ave been obtained after post-dosing 2 L CO to the oxygen-covered surfa ce at cryogenic temperatures.