Physical and chemical properties of high density atomic oxygen overlayers under ultrahigh vacuum conditions: (1x1)-O/Rh(111)

In this paper, we elaborate on our previous communication of high coverages of oxygen on Rh(111) [J. Chem. Phys. 110, 2757 (1999)]. When dosing with O -2, half of a monolayer of O is adsorbed. Higher coverages can be achieved when exposing the surface to O atoms. As the quantity of adsorbed O increas es from a half to a full monolayer, the overlayer structure undergoes sever al distinct phase changes. At a full monolayer, the (1 x 1)-O structure is stable at surface temperatures less than similar to 400 K. Continued dosing with O atoms results in the rapid migration of O into the bulk. We also re port on the chemical reactivity of this densely oxygen-covered surface with CO, H-2, and propene. (C) 2000 American Institute of Physics. [S0021-9606( 00)70404-1].