Structural evolution of medium-sized Pd(n) (n=15-25) clusters from density functional theory.

Four types of possible structural motifs of the medium-sized Pd(n) (n=15-25) clusters i.e., fcc like, decahedron based, icosahedron based, and prolate ellipsoid based, have been generated from an empirical genetic algorithm search and further investigated using spin-polarized density functional theory calculations. fcc-like structures based on Pd(19) octahedron dominate the growth pathway of Pd(n) clusters (n=15-23). For larger clusters such as Pd(24) and Pd(25), a prolate ellipsoid-based geometry and a structure consisting of three interpenetrating decahedra are energetically favorable, respectively. The size-dependent cluster properties as well as the correlation between electronic properties and cluster geometry are also discussed, suggesting a particular stability cluster at Pd(19) with a fcc-like octahedron structure.