Segregation in model palladium-cobalt clusters

N-body Sutton-Chen potentials have been developed for fee Co and the interaction of Co and Pd atoms. These potentials were used to describe the effect of Pd segregation within Pd-Co relaxed clusters. Monte Carlo configurational minimization at room temperature was used to determine the morphology of clusters. For the diffraction patterns averaging over configurations is achieved by molecular dynamics runs. Variation in the position of the 111 peak of the average pattern with cluster alloy composition was compared with X-ray diffraction data for (Pd-Co) silica catalysts. The good fit obtained strongly supports the applicability of the model segregation profile. A key role in the modelling is played by the precise tuning of the Pd-Co potential.