Structural, electronic, and vibrational properties of neutral and charged Nbn (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, and 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 range 100-300 cm(-1) and are sensitive to the structure. Electronic properties an 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. [S1050-2947(98)06312-4].