Surface diffusion and adatom‐induced substrate relaxations of Pt, Pd, and Ni atoms on Pt(001)

Field ion microscope observations show that Pt atoms diffuse on Pt(001) by an adatom–substrate atom replacement mechanism, whereas Pd atoms diffuse on the same surface by site‐to‐site hopping. Ni adatoms are observed to exchange with substrate Pt(001) atoms at temperatures lower than the onset of their migration. The propensity for adatom–substrate atom exchange is found to be correlated with the amount of adatom‐induced substrate relaxation. These relaxations are determined from calculations based on the embedded atom method.