Geometrical and electronic structure of the Ba-doped Sin (n = 1–12) cluster: A density functional study

• The geometric structures of BaSin and Sin+1 (n = 1–12) clusters are determined.
• The stabilities and electronic properties of BaSin clusters are discussed.
• The BaSin (n = 2, 5, 8) have the higher stability than other clusters.
• The charges in BaSin clusters transfers from the Ba atom to Si atom.

The structures, stabilities and electronic properties of BaSin and Sin+1 (n = 1–12) clusters are systematically studied by density functional calculations using the B3LYP exchange–correlation potential. Extensive structure search based on large numbers of initial configurations has been carried out to identify the stable isomers of BaSin (n = 1–12) clusters. We found that the most stable isomers of BaSin clusters are three-dimensional structures when n > 3, and the most stable structures of BaSin clusters often can be created by adding Ba or substituting Si by Ba in pure silicon clusters. The stability has been analyzed based on the average binding energy, fragmentation energy and second-order energy difference. The calculated results indicate that BaSin clusters with n = 2, 5, 8 and 10 have higher stability than other clusters. The analysis of the highest occupied molecular orbital and the lowest unoccupied molecular orbital suggests that the substitution of Ba atom reduce the gaps of the Sin+1 clusters. The Mulliken populations of the Ba atom in the BaSin clusters vary from 0.506 to 1.574, showing that the charges in BaSin clusters transfers from the Ba atom to Si atoms. Furthermore, the vertical ionization potential, vertical electron affinity, chemical hardness, infrared and Raman spectra are also analyzed.