关键词: 笼状化合物;第一性原理;电子结构;稳定性

Abstract: The population and density of states of electrons of Ba_8Si_(46) and Ba_8Ag_6Si_(40) were analyzed in the paper. The Ba_8Si_(46) results show Ba 6s electrons are transferred into the Ba 5d and Si 3p orbits. The sp3 hybridizations of framework Si make the compound posses stabile structure. For Ba_8Ag_6Si_(40), Ag 5s electrons are transferred into the Si 3p orbits.The Ag doping destroys sp3 hybridizations of framework Si. The bond between Ag and Si atoms tends to electrovalent bond. The band structures of Ba_8Si_(46) and Ba_8Ag_6Si_(40) indicate that they are weak metal. Because the band width intersecting with Eermi level for Ba_8Ag_6Si_(40) is larger than Ba_8Si_(46), Ba_8Ag_6Si_(40) compound has higher conductance than Ba_8Si_(46).

Key words: The population and density of states of electrons of Ba_8Si_(46) and Ba_8Ag_6Si_(40) were analyzed in the paper. The Ba_8Si_(46) results show Ba 6s electrons are transferred into the Ba 5d and Si 3p orbits. The sp3 hybridizations of framework Si make the compound posses stabile structure. For Ba_8Ag_6Si_(40), Ag 5s electrons are transferred into the Si 3p orbits.The Ag doping destroys sp3 hybridizations of framework Si. The bond between Ag and Si atoms tends to electrovalent bond. The band structures of Ba_8Si_(46) and Ba_8Ag_6Si_(40) indicate that they are weak metal. Because the band width intersecting with Eermi level for Ba_8Ag_6Si_(40) is larger than Ba_8Si_(46), Ba_8Ag_6Si_(40) compound has higher conductance than Ba_8Si_(46).