Geometries, stabilities and electronic properties of small-sized Pd 2 -doped Si n ( n = 1–11) clusters.

The geometries, growth patterns, relative stabilities and electronic properties of small-sized Pd2Sinand Sin+2(n= 1–11) clusters are systematically studied using the hybrid density functional theory method B3LYP. The optimised structures revealed that the lowest energy Pd2Sinclusters are not similar to those of pure Sinclusters. Whenn= 9, one Pd atom in Pd2Si9completely falls into the centre of the Si outer frame, forming metal-encapsulated Si cages. On the basis of the optimised structures, the averaged binding energy, fragmentation energy, second-order energy difference and highest occupied–lowest unoccupied molecular orbital energy gap are calculated. It is found that the Pd2Si5and Pd2Si7clusters have stronger relative stabilities among the Pd2Sinclusters. Additionally, the stabilities of Sin+2clusters have been reduced by the doping of Pd impurity. The natural population and natural electronic configuration analysis indicated that the Pd atoms possess negative charges forn= 1–11 and there exist the spd hybridisation in the Pd atom. Finally, the chemical hardness, chemical potential, electrostatic potential and polarisability are discussed. [ABSTRACT FROM PUBLISHER]