Energetic and Structural Analysis of 102-Atom Pd-Pt Nanoparticles: A Composition-Dependent Study

We present an extensive study of the structural and energetic changes of 102-atom PdmPt102-m nanoparticles as a function of composition m, where the interatomic interactions are modeled with the many-body Gupta potential. The minimum energy structures are obtained through a genetic algorithm. The excess energy is calculated, as well as the radial distribution of atoms, n(r), which is computed for each composition. The results indicate a multi-layer segregation for some compositions, with a shell growth sequence as follows a core with a small number of Pd atoms is followed by an intermediate shell of Pt atoms and the external shell consists of Pd atoms. A region where Pd and Pt atoms are mixed is observed between the outermost and intermediate shells. Furthermore, the pure Pd-102 and Pt-102 nanoparticles have capped Marks decahedron structures, while several different lowest energy structures are observed for the bimetallic clusters in the range of compositions studied here.