Relativistic and nonrelativistic structures, stabilities and electronic properties of small neutral gold clusters

This work uses the nonrelativistic and scalar-relativistic second-order Douglas-Kroll-Hess (DKH2) Hamiltonians together with the all-electron basis sets to determine the structures, stabilities and electronic properties of the small neutral gold clusters, Au-n (n <= 6). Several levels of theory including the all-electron scalar-relativistic DKH2-M06HF/TZP-DKH, DKH2-B3LYP/TZP-DKH and DKH2-B3LYP/DZP-DKH along with the nonrelativistic B3LYP/DZP are used to calculate the static polarizabilities, polarizability anisotropies, second difference of the cluster energies, fragmentation energies, binding energies, the highest occupied-lowest unoccupied (HOMO-LUMO) energy gaps, ionization potentials and electron affinities of the small gold clusters. We find that the vertical ionization potentials and adiabatic electron affinities are in good agreement with the experimental data at the DKH2-B3LYP/DZP-DKH level of theory, while the best bond length and geometries are obtained at the DKH2-M06HF/TZP-DKH level.