Lifting the Pt{100} surface reconstruction through oxygen adsorption: A density functional theory analysis

The adsorption of atomic oxygen on unreconstructed Pt{100}-(1x1) and reconstructed Pt{100}-(5x1) was modeled using density-functional theory in an attempt to understand the relative stability of the unreconstructed phase as a function of oxygen coverage. Our calculations showed that at zero temperature the (5x1) is more stable than the unreconstructed (1x1) phase at zero oxygen coverage. However, oxygen absorption on the Pt{100}-(5x1) phase removed the reconstruction, reversing the phase stability. Using thermochemical analysis, we show desorption of oxygen corresponding to a temperature near 730 K, consistent with experimentally observed desorption peaks for oxygen covered (1x1) surfaces. These results have ramifications for understanding the full Pt{100}(1x1)-> Pt{100}-hex-R0.7 degrees surface phase transition. (c) 2005 American Institute of Physics.