A density functional study of bare and hydrogenated platinum clusters

We perform density functional theory calculations using Gaussian atomic-orbital methods within the generalized gradient approximation for the exchange and correlation to study the interactions in the bare and hydrogenated platinum clusters. The minimum-energy structures, binding energies, relative stabilities, vibrational frequencies and the highest occupied and lowest unoccupied molecular-orbital gaps of PtnHm (n = 1-5, m = 0-2) clusters are calculated and compared with previously studied pure platinum and hydrogenated platinum clusters. We investigate any magic behavior in hydrogenated platinum clusters and find that Pt4H2 is more stable than its neighboring sizes. The lowest energy structure of Pt4 is found to be a distorted tetrahedron and that of Pt5 is found to be a bridge site capped tetrahedron which is a new global minimum for Pt5 cluster. The successive addition of H atoms to Ptn clusters leads to an oscillatory change in the magnetic moment of Pt3-Pt5 clusters.