材料期刊网

An ab initio method based on the density functional theory has been employed to investigate the behaviours of the bimetallic Ag(2)-doped silicon clusters at a size of n = 1-11. The possible geometrical configurations, growth-pattern behaviours, stabilities, energy gaps, and electronic properties are presented and discussed. The optimized geometries reveal that the silicon atom surface-capped and silver atom substituted 3D structures are dominant growth patterns. The calculated averaged binding energy, fragmentation energy, and the second-order difference of energy manifest that the most stable structures of Ag(2)Si(n) (n = 1-11) clusters are Ag(2)Si(2) and Ag(2)Si(5) isomers, which is in qualitative agreement with the AgSi(n) clusters. In addition, the gap between highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO) exhibits that the Ag(2)Si(3) and Ag(2)Si(5) isomers have dramatically enhanced chemical stability. Natural population analysis shows that the charge-transfer phenomena are coincidence with the AgSi(n) clusters but different from Mo(2)Si(n) systems. Furthermore, the dipole moments of stable Ag(2)Si(n) (n = 1-11) display a pronounced odd-even oscillation with the number of silicon atoms.