Structural and electronic properties of tungsten nanoclusters by DFT and basin-hopping calculations

Abstract

The structural and electronic properties of small tungsten nanoclusters W_n (n = 2–16) were investigated by density functional theory (DFT) calculations. For the W nanocluster, the lowest-energy structures were first obtained by the basin-hopping method (BH) with the tight-binding many-body potential for a bulk tungsten material. These structures were further optimized by DFT calculations in order to find better parameters of the tight-binding (TB) and Finnis–Sinclair (FS) potential appropriate for W nanoclusters. The values of binding energy and second-order energy difference reveal that the structure W₁₁ has a higher stability than those of other sizes. The vertical ionization potential (VIP), adiabatic electron affinity (AEA) and HOMO–LUMO gap are also discussed for W nanoclusters of different sizes. In addition, large size nanoclusters W_n (n = 30–120) are obtained by the BH method, and a comparison of the structural properties determined by TB and FS potentials are represented with Honeycutt–Andersen index analysis.