Structural, Electronic and Vibrational Properties of Neutral and Charged Nb(n) (n=8, 9, 10) Clusters

We present a theoretical study of the structural, vibrational, and electronic properties of small niobium clusters (Nb(8), Nb(9), Nb(10)) using density functional theory with local as well as gradient-corrected exchange correlation density functionals. For Nb(8) and Nb(9), several low-energy structures were obtained, whereas for Nb(10) there seems to be only one isomer that is energetically preferred. Vibrational spectra are in the 100--300 cm**-1 range and are sensitive to the structure. Electronic properties are investigated by means of the densities of states, which depend strongly on the geometry. The theoretical results for the ionization potentials and vertical detachment energies are in good agreement with available experimental data.