Density functional studies of small platinum clusters

We present results of a density functional theory study of the structure and energetics of small Pt clusters. The method of calculation is based on the non-selfconsistent Harris functional version of LDA (as formulated by Sankey and Niklewski, and generalized to include d orbitals in the basis set), which produces excellent results for bulk Pt. We used a dynamical quenching algorithm to obtain minimum-energy structures of Pt-n clusters for n = 2-6. The clusters with n = 4-6 are shown to be planar. For Pt-13 we found that there is a variety of low-symmetry geometries that are lower in energy than the icosahedral and cube-octahedral structures. We also compute the vibrational states of n = 2-4, and show that the calculated vibrational frequency and bond energy of the Pt dimer are in good agreement with experiments.