Bimetallic Ni/Pd finite systems: Structure and thermodynamics of bimetallic Ni/Pd nanostructures in two and three dimensions

By implementing replica-exchange Monte Carlo simulations within the multihistogram reweighting techniques, the structural and thermodynamic changes in bimetallic nickel–palladium nanostructured systems were studied as a function of composition. Specifically, two- and three-dimensional clusters composed of seven and thirteen atoms, respectively, were described using the embedded atom potential. The lowest energy equilibrium structures were determined, and associated to the degree of mixing in the material. In all cases, melting and order–disorder transitions were revealed by calculating the average constant volume heat capacity as a function of temperature. The change in Helmholtz free energy for the order–disorder transition was determined as a function of composition for each system.