Oriented oxygen admolecules on a stepped platinum 133/surface

Oxygen admolecules on stepped Pt 133.s s.3 111.= 111.were characterized by thermal desorption spectroscopy and near-edge X-ray absorption fine structure. Three admolecule desorption peaks were found at 150 K a3-O2., 175 K a2-O2. and 220 K a1-O2.. The admolecule yielding a1-O2 lies along the trough, whereas a2-O2 and a3-O2 lie on declining 111. terraces and are inclined about 358 and 508 from the trough direction, respectively. q1998 Elsevier Science B.V. All rights reserved.