Electronic structure and ground states of transition metals encapsulated in a Si12 hexagonal prism cage -: art. no. 155404

We report on a computational study of the electronic structure of recently discovered clusters with an encapsulated transition metal (TM) atom in a Si-12 hexagonal prism cage. The cage geometry is remarkably stable regardless of the type of doping TM atom from 3d, 4d, and 5d series. We predict and quantify the stability for several other TM dopings besides the experimentally observed ones. The multiplicity of the ground states can be "tuned" between singlets and triplets by varying the type of TM atom (even number of electrons), while they are doublets for odd number of electrons. We also explore the possibility of forming solids with hexagonal structure from selected clusters.