Structural and dynamical properties of Cu–Au bimetallic clusters

The effect of alloying on the structural and thermal properties of Cun−xAux (n=13,14) clusters is investigated by constant energy Molecular Dynamics simulations. The interactions between the atoms in the clusters are mimicked by a many‐body (Gupta‐like) potential based on the second moment approximation to the tight‐binding model. The minimum energy structures and the lowest‐lying isomers of the pure and mixed clusters are obtained by thermal quenching. We find icosahedral‐like ground state structures for the 13‐ and 14‐atom clusters and for all the concentrations, the only exception being Au14 which has C6v symmetry. Mixed structures are preferred over the segregated ones. The lowest‐lying isomers of the binary clusters are the permutational ones, i.e., isomers having the same underlying geometry as the ground state structure and different relative arrangement of the unlike atoms in the atomic positions of the geometry. However, presence of these low lying permutational isomers does not affect the gross ...

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