Adsorption and Vibration of O Atoms on Fe Low-index and Fe(211) High-index Surfaces*

The 5-parameter Morse potential (5-MP) of the interaction between oxygen atoms and iron surfaces was constructed. The adsorption and diffusion of O atoms on Fe low-index and Fe(211) high-index surfaces were investigated by using 5-MP. All the critical characteristics of the system, such as adsorption site, adsorption geometry, binding energy, and eigenvalues for vibration, were calculated. The calculation results show that O atoms are located at the fourfold hollow site of the Fe(100) surface with an eigenvibration at 437 cm−1. These results are in good agreement with the experimental and theoretical results obtained previously. With regard to the adsorption site of O-Fe(110) system, the authors of this study assume that the preferential adsorption state is the H3 site and not the LB site, which is not in agreement with the experimental inferences obtained earlier. However, on the Fe(111) and Fe(211) surfaces, O atoms predominantly occupy the quasi-3-fold site.