Geometries, stabilities, electronic and magnetic properties of small aluminum cluster anions doped with cobalt: A density functional theory study

摘要

The geometrical structures, relative electronic and magnetic properties of small Al (n) Co- (1 a parts per thousand currency sign n a parts per thousand currency sign 9) clusters are systematically investigated within the framework of density functional theory at the BPW91 level. The single Co doping can dramatically affect the ground state geometries of the 1 Al (n+1) (-) clusters. At the same time, the resulting geometries show that the lowest energy Al (n) Co- clusters prefer to be three dimensional structures. Here, the relative stabilities are investigated in terms of the calculated average binding energies, fragmentation energies, and second-order energy differences. Moreover, the result of the highest occupiedlowest unoccupied molecular orbital energy gaps indicates that Al6Co- clusters have the highest chemical stability for Al (n) Co- (1 a parts per thousand currency sign n a parts per thousand currency sign 9) clusters. Furthermore, the natural population analysis reveals that the charges in Al (n) Co- clusters transfer from the Al frames to the Co atom. Additionally, the analyses of the local and total magnetic moments of the Al (n) Co- clusters show that the magnetic effect mainly comes from the Co atom.