ADSORPTION SITES AND MIGRATION OF A CARBON-MONOXIDE MOLECULE ON STEPPED VICINAL SURFACES OF CU(211) AND CU(511)

Motivated by recent scanning tunneling microscopy (STM) and helium-ato m scattering experiments, the adsorption of a carbon monoxide molecule on Cu(211) and Cu(511) stepped vicinal surfaces is studied by analyzi ng the interaction potential and performing classical dynamics simulat ions both in the canonical and microcanonical ensembles. For both (211 ) and (511) surfaces we found two adsorption sites, nearly equivalent energetically, located nearly on top above the border-row atoms of a t errace. These sites, favored by a large available phase space, have th e highest adsorption probability in agreement with STM results on the CO/Cu(211) system. At low temperatures hindered translation of CO is a nisotropic along the different crystallographic directions. For both s urfaces, the migration is favored along rows but there are significant differences between Cu(211) and Cu(511). (C) 1998 Elsevier Science B. V. All rights reserved.