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

摘要

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 Al 12X (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 Al 12X (X = Sc, Ti, V, Ni, Cu) clusters. The magnetic moments of the doped Al 12X (X = Cr, Mn and Fe) are substantially increased as compared with that of the pure Al 13, 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 Al 12X 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 Al 13, 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.