Appearance of metallic features in small tungsten clusters

The structures and properties of W_n (n=2--14) clusters were studied by using the density functional theory (DFT) at LSDA level. The most stable structures of W_n (n=2--14) clusters with global minimum were determined. The average binding energy (E_b), the first and second difference of total energy (\it\Delta E, \it\Delta_2E), the vertical detachment energy (VDE), and the HOMO-LUMO gap versus the size were also discussed. The abrupt decrease of VDE and HOMO-LUMO gap at size n=8 and 10 implied that tungsten clusters of W_8 and W_10 appeared to have metallic features. These changes were also accompanied by the delocalization of electron charge density and the strong hybridization between 5d and 6s orbits in W_8 and W_10 clusters. Our results are in good agreement with the available experimental data.