Density functional study of Auₙ (n=2-20) clusters: lowest-energy structures and electronic properties

الأصل · EN

We have investigated the lowest-energy structures and electronic properties of the Auₙ(n=2-20) clusters based on density functional theory (DFT) with local density approximation. The small Auₙ clusters adopt planar structures up to n=6. Tabular cage structures are preferred in the range of n=10-14 and a structural transition from tabular cage-like structure to compact near-spherical structure is found around n=15. The most stable configurations obtained for Au₁₃ and Au₁₉ clusters are amorphous instead of icosahedral or fcc-like, while the electronic density of states sensitively depend on the cluster geometry. Dramatic odd-even alternative behaviors are obtained in the relative stability, HOMO-LUMO gaps and ionization potentials of gold clusters. The size evolution of electronic properties is discussed and the theoretical ionization potentials of Auₙ clusters compare well with experiments.