The 13-atom encapsulated gold cage clusters

The structure and the magnetic moment of transition metal encapsulated in a Au12 cage cluster have been studied by using the density functional theory. The results show that all of the transition metal atoms (TMA) can embed into the Au12 cage and increase the stability of the clusters except Mn. Half of them have the Ih or Oh symmetry. The curves of binding energy have oscillation characteristics when the extra-nuclear electrons increase; the reason for this may be the interaction between parity changes of extra-nuclear electrons and Au atoms. The curves of highest occupied molecular orbital—lowest unoccupied molecular orbital (HOMO—LUMO) gap also have oscillation characteristics when the extra-nuclear electrons increase. The binding energies of many M@Au12 clusters are much larger than that of the pure Au13 cluster, while the gaps of some of them are less than that of Au13, so maybe Cr@Au12, Nb@Au12, and W@Au12 clusters are most stable in fact. For magnetic calculations, some clusters are quenched totally, but the Au13 cluster has the largest magnetic moment of 5 μB. When the number of extra-nuclear electrons of the encapsulated TMA is even, the magnetic moment of relevant M@Au12 cluster is even, and so are the odd ones