Size-selective effects in the geometry and electronic property of bimetallic Au-Ge nanoclusters

► Size-selective effects of some properties on clusters are studied using DFT method. ► The AuGe8- and AuGe9- structures are rearranged due to addition of an extra electron. ► Magic number of cagelike AuGen- clusters is favored at n = 10, the most stable one for n = 12. ► The HOMO-LUMO gaps show a decreased tendency along with the increasing size. ► AEA, VEA and VDE of the most stable clusters were obtained and discussed in detail.