The Research For Geometry And Properties Of Pd, Pb And H Micro-clusters

The cluster of palladium is one of the clusters that have come to Attention in recent years. This is because its special physical and chemical .The palladium and the alloy of palladium and other metals (e.g. Ag, Y and Pb) are used as the catalyst in chemical reaction and sorbing material widely. Because hydrogen is easy absorbed by them, palladium and its alloy are used in purification and separation of hydrogen. In this paper, all of works have been calculated by use of the density function theory (DFT) Beck 3LYP method with relativistic effective core potential (RECP) and Gaussian98 program. The ground-state structure, spectral properties, energy level distribution and the electronic properties of cluster of Pb_n(n=1—9), Pd_nPb(n =1-7), Pd_nPbH(n = 1 - 6) and Pd_nPb_m(n+m≤5) are researched systematically:(1) The research result of cluster Pb_n(n=2-9) indicate that the "odd-even" and "magic numbers" effect don't exist in Fermi levels,energy gaps and ionization potentials. The turning point that planar structure translates into spatial structure is n=5. The stability of cluster is strong gradually. The chemical activity of lead is smaller than that of palladium.(2) Geometric and electronic properties of Pd_nPb(n≤7) clusters and Pd_nPb_m (n+m ≤5) are studied using density functional theory with effective core potentials, focusing on the differences between mono and bimetallic clusters.The most stable structure of Pd_nPb (n≤6) is singlet. The ground state of Pd is singlet, and triplet for Pb, and then there is at least a Pd or Pb atom on its excited state. The energy gaps of the Pd-Pb binary clusters are narrower than those of the Pd_n clusters, then the...