| Abstract
| - The adsorption, vibration, and diffusion of O atoms on Rh(100), Rh(111), Rh(110), and Rh(711) surfaceswere studied using the 5-parameter Morse potential (5-MP) of interaction between an adatom and a metalsurface cluster. Our theoretical calculations provide information about adsorption sites, adsorption geometry,binding energy, and eigenvibration. Our results agreed very well with experimental results. Four major resultsfollow. First, the theoretical calculation showed that on the Rh(100) surface the 4-fold hollow site is the onlyadsorption site. Second, on the O−Rh(111) system, the 3-fold hollow site is the stable adsorption site. Third,on the Rh(110) surface at low coverage, the O atom is adsorbed preferably on the pseudo-3-fold site, whilewith increasing coverage, the O atom is adsorbed not only on the pseudo-3-fold site but also on the longbridge site. Last, as for the Rh(711) stepped surface, the 3-fold site on the (111) step is metastable, whereasthe 4-fold sites on the (100) terrace are stable, which enables the O atoms to diffuse easily from the 3-foldto the 4-fold site at low coverage. Therefore, the O atoms are adsorbed preferrably on the stable 4-fold sitesof the (100) terrace and then later as coverage increases on the metastable 3-fold site of the (110) step.
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