The first-principles study of Al12X (X = Sc-Zn) clusters and their adsorption of H, O and N

Abstract

Started from the four types 13-atom high-symmetric (Ih, Oh, D5h, D3h) close-packed structures and by replacing a 3d transition metal atom in the nonequivalent position, the geometrical and electronic properties of the doped Al12X (X = Sc-Zn) clusters are systematically studied by using the density-functional theory. Close-packed (icosahedral-like) structures are found to be favorable for the ground state geometries and the degenerate isomers of Al12X (X = Sc, Ti, V, Ni, Cu) clusters. The magnetic moments of the doped Al12X (X = Cr, Mn and Fe) are substantially increased as compared with that of the pure Al13, which are mainly derived from the strong spin splitting of the d electrons of the doped atoms. For the absorption of H, O and N on the close-packed Al12X clusters, it is found that H atom tend to occupy the top or bridge site instead of the hollow site, but the adsorption sites of O and N atom are more complex. O and N are always adsorbed around the doped atom of the doped cluster with the doped atom on the surface and the adsorption energies of O and N on the doped clusters are all enhanced as compared with that on pure Al13, but it is quite different for the adsorption of H, which implies that the influences of the d electrons of the doped atoms on O and N are stronger than that on H. All doped clusters exhibit the same selective sequence of adsorption: O > N > H.