Growth pattern of doubly metal doped silicon clusters M2Sin with M2 = Mo2, Nb2, Ta2, W2, NbMo, TaW and n=11-18. Formation of fused cages M2Si18

Geometries of doubly transition metal doped silicon clusters M(2)Sin, M-2 = Mo-2, Nb-2, Ta-2, W-2, NbMo, TaW were determined by DFT computations. Geometries of M(2)Sin in the range from 11 to 18 Si atoms change from a tubular shape to a cage and then a fused cage. The M2Si18 sizes present us with a novel structural motif, the fused cage, for silicon clusters. Such fused cages arise from a fusion of both MSi10 and MSi12 prisms followed by addition of two Si atoms. Formation and filling of electron shells contribute to the high thermodynamic stability of M2Si18 fused clusters.

Automated summary

The geometries of doubly transition metal doped silicon clusters M(2)Sin were determined by DFT computations. It was found that the structures of M(2)Sin clusters change from tubular to cage-like and then fused cage-like with the increase of Si atoms. The fused cage structure of M2Si18 has a novel structural motif and the thermodynamic stability is attributed to the formation and filling of electron shells.