Structures and electronic properties of Cu20, Ag20, and Au20 clusters with density functional method

We have investigated the lowest-energy structures and electronic properties of the 20-atoms coinage metal clusters (Cu-20, Ag-20, and Au-20) using density functional theory (DFT) within generalized gradient approximation. The most stable configurations obtained for Ag-20 and Au-20 clusters are tetrahedral structures T-d symmetry), while compact structure with C-s symmetry is preferred for Cu-20. Large HOMO-LUMO gap is found for Au-20 and Ag-20 with tetrahedral structures, while it is much small in the Cu-20 isomer with tetrahedral structures. The compact C-s structure of Cu-20 has large gap comparable to that of Au-20 with tetrahedral structure. (C) 2003 Elsevier B.V. All rights reserved.