SURFACE STRUCTURAL TRANSFORMATIONS DURING AMMONIA OXIDATION ON RH(110)

A metastable surface structure, which mediates the conversion from an O-induced (1 X 4) to N-induced (2 X 1) substrate reconstruction, is observed by scanning tunneling microscopy during the oxidation of ammonia on Rh(110). The units of the metastable phase are short three-atomic segments of [001] Rh rows forming a hexagonal superlattice of a c(2 X 6) symmetry. The issue of this study is the impact of the initial structural anisotropy of the surface on the mass transport and elementary steps of the structural transformations resulting in an intermediate that cannot be formed by either of the reaction participants alone.