Electronic structure and magnetic properties of Ni clusters

A systematic study on the ground state electronic structure and magnetic pr operties of Ni-n (n = 2-39 and 55) clusters are performed using the density functional calculation with the local spin-density approximation. The bind ing energy per atom increases monotonically. The occupation numbers do not change significantly for n > 8, which helps us to understand the experiment al observation of the photoelectron spectroscopy. The obtained average magn etic moment per atom is larger than the bulk value, and the evolvement of t hese moments towards the bulk is in good agreement with the experimental tr end. However, the average moments of "core" atoms are comparable to or even larger than that of surface atoms, which indicates that the usual conclusi on of surface enhancement on magnetism in transition metal clusters may be improper for these Ni-n (n = 14-39) clusters. (C) 2001 American Institute o f Physics.