DENSITY-FUNCTIONAL STUDIES OF SMALL PLATINUM CLUSTERS

We present results of a density functional theory study of the structu re and energetics of small Pt clusters. The method of calculation is b ased on the non-selfconsistent Harris functional version of LDA (as fo rmulated by Sankey and Niklewski, and generalized to include d orbital s in the basis set), which produces excellent results for bulk Pt. We used a dynamical quenching algorithm to obtain minimum-energy structur es of Pt-n clusters for n = 2-6. The clusters with n = 4-6 are shown t o be planar. For Pt-13 we found that there is a variety of low-symmetr y geometries that are lower in energy than the icosahedral and cube-oc tahedral structures. We also compute the vibrational states of n = 2-4 , and show that the calculated vibrational frequency and bond energy o f the Pt dimer are in good agreement with experiments.