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[摘要]：Endohedral 1st-row transition-metal-doped TM niSi nanoclusters, in which TM stands for the 1st-row transition-metals from Sc to Zn, and i = 12, 16, were characterized. In these structures the dopant metals are trapped inside spheroidal hollow semiconducting nanoclusters. Some of the transition metals are trapped in the center of mass of the cluster, whereas others are displaced from that center, leading to structures in which the transition metals display a complex dynamical behavior upon encapsulation. This fact was confirmed by quantum mol. dynamics calcns., which further confirmed the thermal stability of endohedral compds. In the endohedrally-doped nanoclusters in which the transition-metal atom sits on the center of mass, the host hollow cluster structure remains undistorted after dopant encapsulation. Conversely, if the encapsulated transition-metal atom is displaced from the center of mass, the host hollow cluster structure suffers a very tiny distortion. Addnl., there is negligible charge transfer between the dopant transition-metal atom and its hollow cluster host and, after encapsulation, the spin densities remain localized on the transition-metal atom. This allows for the at.-like behavior of the trapped transition-metal atom, which gives rise to their at.-like magnetic properties. The encapsulation free energies are neg., suggesting that these compds. are thermodynamically stable. |
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