  40 is a magic number for tetrahedral symmetry predicted in both nuclear
physics and the electronic jellium model. We show that Au40 could be such a a
magic cluster from density functional theory-based basin hopping for global
minimization. The putative global minimum found for Au40 has a twisted pyramid
structure, reminiscent of the famous tetrahedral Au20, and a sizable HOMO-LUMO
gap of 0.69 eV, indicating its molecular nature. Analysis of the electronic
states reveals that the gap is related to shell closings of the metallic
electrons in a tetrahedrally distorted effective potential.
