Structural, Relative Stable, and Electronic Properties of PbnSnn (n=2-12) Clusters were Investigated Using Density Functional Theory

摘要

The structural, relative stable and electronic properties of PbnSnn (n = 2-12) alloy clusters were systematically studied using density functional theory. The isomers of PbnSnn alloy clusters were generated and determined by ab initio molecular dynamics. By comparing the calculated parameters of Pb-2 dimer and Sn-2 dimers with the parameters from experiments, our calculations are reasonable. With the lowest-energy structures for PbnSnn clusters, the average binding energies, fragmentation energies, second- order energy differences, vertical ionization potentials, vertical electron affinities, HOMO-LUMO gaps, and density of states were calculated and analyzed. The results indicate that the Sn atoms have a tendency to bond together, the average binding energies tend to be stable up to n = 8, Pb8Sn8 cluster is a good candidate to calculate the molecular interaction energy parameter in Wilson equation, the clusters become less chemical stable and show an insulator-to-metallic transition, 3, 6, 8 and 11 are magic numbers of PbnSnn (n = 2-12) clusters, the charges always transfer from Sn atoms to Pb atoms in PbnSnn clusters except for Pb10Sn10 cluster, and density of states of PbnSnn clusters becoming continuous and shifting toward negative with the increasing size n.