Cagelike Si 12 clusters with endohedral Cu, Mo, and W metal atom impurities
Cagelike Si 12 clusters with endohedral Cu, Mo, and W metal atom impurities
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具有内嵌 Cu、Mo 和 W 金属原子杂质的笼状 Si 12 团簇
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
W. A. Lester
中科院分区：
文献类型：
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作者：
F. Hagelberg;C. Xiao;W. A. Lester
In a recent series of mass-spectrometric ion trap measurements [H. Hiura et al., Phys. Rev. Lett. 86, 1733 (2001)], the formation of silicon clusters with endohedral transition-metal impurities was observed. Particular stability was assigned to the experimentally detected species ${mathrm{WSi}}_{12}^{+},$ which has been shown by ab initio geometry optimization to adopt the shape of a regular hexagonal ${mathrm{Si}}_{12}$ prism with the W atom in the center. A similar geometrychar22{}namely, a ${mathrm{Si}}_{12}$ double-chair structure surrounding the metal atom impuritychar22{}has emerged from our extensive investigations of silicon clusters in combination with a Cu atom $({mathrm{CuSi}}_{N})$ as the likely ground-state structure of ${mathrm{CuSi}}_{12}.$ These results suggest the systematic importance of ${mathrm{Si}}_{12}$ cages derived from regular structures with ${D}_{6h}$ geometry for the architecture of silicon clusters containing metal atom impurities. In the present comparative study, we discuss the salient features of endohedral $M{mathrm{Si}}_{12}$ clusters with $M=mathrm{Cu},$ Mo, W, as well as several cationic and anionic species of these systems, with regard to their geometric and electronic structure. The interaction between the ${mathrm{Si}}_{12}$ cage and the enclosed metal impurity is characterized as strongly delocalized bonding for $M=mathrm{Mo},$ W, while Cu tends to form directed bonds with selected atoms of the cage. Linear extension of the $M{mathrm{Si}}_{12}$ $(mathrm{M}mathrm{e}=mathrm{M}mathrm{o},mathrm{W})$ cells along their principal axes leads to units of the form ${M}_{2}{mathrm{Si}}_{18}.$
In a recent series of mass-spectrometric ion trap measurements [H. Hiura et al., Phys. Rev. Lett. 86, 1733 (2001)], the formation of silicon clusters with endohedral transition-metal impurities was observed. Particular stability was assigned to the experimentally detected species ${mathrm{WSi}}_{12}^{+},$ which has been shown by ab initio geometry optimization to adopt the shape of a regular hexagonal ${mathrm{Si}}_{12}$ prism with the W atom in the center. A similar geometrychar22{}namely, a ${mathrm{Si}}_{12}$ double-chair structure surrounding the metal atom impuritychar22{}has emerged from our extensive investigations of silicon clusters in combination with a Cu atom $({mathrm{CuSi}}_{N})$ as the likely ground-state structure of ${mathrm{CuSi}}_{12}.$ These results suggest the systematic importance of ${mathrm{Si}}_{12}$ cages derived from regular structures with ${D}_{6h}$ geometry for the architecture of silicon clusters containing metal atom impurities. In the present comparative study, we discuss the salient features of endohedral $M{mathrm{Si}}_{12}$ clusters with $M=mathrm{Cu},$ Mo, W, as well as several cationic and anionic species of these systems, with regard to their geometric and electronic structure. The interaction between the ${mathrm{Si}}_{12}$ cage and the enclosed metal impurity is characterized as strongly delocalized bonding for $M=mathrm{Mo},$ W, while Cu tends to form directed bonds with selected atoms of the cage. Linear extension of the $M{mathrm{Si}}_{12}$ $(mathrm{M}mathrm{e}=mathrm{M}mathrm{o},mathrm{W})$ cells along their principal axes leads to units of the form ${M}_{2}{mathrm{Si}}_{18}.$