The geometrical structures, relative stabilities, and electronic properties of small bare gold clusters Au(n)(lambda) and bimetallic complexes of bare metal clusters with one copper atom Au(n-1)Cu(lambda) (charge lambda = 0, +1, -1; 2 < or = n < or = 9) have been systematically investigated by means of first-principles density functional calculations at the B3LYP level. The results show that the most stable isomers have a planar structure and resemble pure gold clusters in shape, and no three-dimensional isomers were obtained for neutral and anionic doped gold clusters. However, the geometries of Au(n-1)Cu(+) are found to undergo a structural change from two dimensional to three dimensional when the cluster contains 7 atoms. The calculated dissociation energy and second difference energy as a function of the cluster size exhibit a pronounced even-odd alternation phenomenon. Ionization potentials and electron detachment energies (both vertical and adiabatic) of Au(n)(lambda) and Au(n-1)Cu(lambda) clusters are discussed and compared with available experimental results. A good agreement between experimental and theoretical results suggests good prediction of the lowest energy structures for all clusters calculated in the present study.

The golden Au16(q) (q = 0, -1) cage is doped systematically with an external atom of different valence electrons: Sc, Ti, and V. The structural, electronic, and magnetic properties of the doped clusters, M@Au16(q) (M = Sc, Ti and V; q = 0, -1) are investigated using the Saunders "Kick" (SK) global search technique combined with density-functional theory (DFT) calculations (SK-DFT). It is found that the closeness of the calculated vertical/adiabatic detachment energy for Ti-doped and V-doped (3.09/3.16 eV for Ti-doped, and 3.31/3.38 eV for V-doped) is consistent with the negligible geometry change between the anionic and neutral ground state structures. The characteristics of the Sc@Au16(-) cluster includes its remarkably high average binding energy and doping energy, which reflects its high stability. The different spectral features between doped M@Au16(-) and pure Au16(-) clusters indicate endohedral structures with larger distortion from the parent Au16(-) cage for the doped clusters. The s electrons of the Au16 cage are observed to transfer to Sc, Ti and V atom for doped M@Au16(q) clusters by natural population analysis (NPA). The magnetic moment of the impurity Sc/Ti/V atom is somewhat quenched. Furthermore, the electron localization function analysis does not reveal strong interactions. The current work shows that the electronic properties of the golden cage can be systematically tuned through doping.

The structural evolution and bonding of a series of early transition-metal oxide clusters, V(n)O(q) (n = 3-9, q = 0,-1), have been investigated with the aid of previous photoelectron spectroscopy (PES) and theoretical calculations. For each vanadium monoxide cluster, many low-lying isomers are generated using the Saunders "Kick" global minimum stochastic search method. Theoretical electron detachment energies (both vertical and adiabatic) were compared with the experimental measurements to verify the ground states of the vanadium monoxide clusters obtained from the DFT calculations. The results demonstrate that the combination of photoelectron spectroscopy experiments and DFT calculation is not only powerful for obtaining the electronic and atomic structures of size-selected clusters, but also valuable in resolving structurally and energetically close isomers. The second difference energies and adsorption energies as a function of the cluster size exhibit a pronounced even-odd alternation phenomenon. The adsorption energies of one O atom on the anionic (6.64 → 8.16 eV) and neutral (6.41 → 8.13 eV) host vanadium clusters are shown to be surprisingly high, suggesting strong capabilities to activate O by structural defects in vanadium oxides.

Structures and simulated photoelectron spectra of MSi6− (M = La, Ce, Yb and Lu).