ABSTRACT
Using a combination of density functional theory and anion photoelectron spectroscopy experiment, we have studied the structure and electronic properties of CuCl(n)(-) (n = 1-5) and Cu(2)Cl(n)(-) (n = 2-5) clusters. Prominent peaks in the mass spectrum of these clusters occurring at n = 2, 3, and 4 in CuCl(n)(-) and at n = 3, 4, and 5 in Cu(2)Cl(n)(-) are shown to be associated with the large electron affinities of their neutral clusters that far exceed the value of Cl. While CuCl(n) (n ≥ 2) clusters are conventional superhalogens with a metal atom at the core surrounded by halogen atoms, Cu(2)Cl(n) (n ≥ 3) clusters are also superhalogens but with (CuCl)(2) forming the core. The good agreement between our calculated and measured electron affinities and vertical detachment energies confirm not only the calculated geometries of these superhalogens but also our interpretation of their electronic structure and relative stability.
ABSTRACT
A synergistic approach combining the experimental photoelectron spectroscopy and theoretical electronic structure studies is used to probe the geometrical structure and the spin magnetic moment of Co(n)(pyridine)(m) (-) clusters. It is predicted that the ground state of Co(pyridine)(-) is a structure where the Co atom is inserted in a CH bond. However, the insertion is marked by a barrier of 0.33 eV that is not overcome under the existing experimental conditions resulting in the formation of a structure where Co occupies a site above the pyridine plane. For Co(2)(pyridine)(-), a ground-state structure is predicted in which the Co(2) diametric moiety is inserted in one of the CH bonds, but again because of a barrier, the structure which matches the photoelectron spectrum is a higher-energy isomer in which the Co(2) moiety is bonded directly to nitrogen on the pyridine ring. In all cases, the Co sites have finite magnetic moments suggesting that the complexes may provide ways of making cluster-based magnetic materials.
