DENSITY-FUNCTIONAL STUDY OF NIOBIUM CLUSTERS

We describe local and nonlocal Gaussian orbital-spin-polarized density-functional calculations for clusters of two to seven niobium atoms. The most stable geometries found with geometry optimization have a high atomic coordination. The trends in the experimental binding energies, bond dissociation energies, and ionization potentials are well reproduced with the exception of the pentamer bond dissociation energy, which is too low. The possible causes are discussed. These are the most extensive state-of-the-art calculations to date for the clusters of a transition metal.