Cobalt clusters (Con, n ⩽ 6) and their anions

The structural, electronic, and magnetic properties of Con (n ⩽ 6) clusters and their anions have been investigated using the density functional theory with effective core potentials and the generalized gradient correction. The ground state optimal geometries and the next low lying local minima have been obtained. For the neutral Con (3 ⩽ n ⩽ 6) clusters, a linear structure, an out-off-plane rhombus, a planar W-like structure, and a distorted octahedron has been identified as the global minima, respectively. The addition of an electron to the neutral clusters do not change the geometric motifs significantly. As the number of atoms in the Co clusters increases, the total spin magnetic moment rises. For n > 2, the ground state total spin moment (M) of the neutral Co clusters studied in the present work obeys the rule that M = 2n + a where a = 1 if n is odd, and a = 2 if n is even. For the anionic clusters, the total spin moment is equal to M − 1.