First-principles study of the stability and Jahn-Teller distortion of nickel clusters

The density functional method for molecules has been employed to study the structural and magnetic properties of NiN (N=2-13) clusters. The calculated results show that the Jahn-Teller effect plays an important role in determining the ground state of certain geometric structures. Ground states have been assigned for these clusters. For Ni5 and Ni7, new ground states have been found. The second derivative of the binding energy with cluster size shows that besides N=13, N=10 is also a magic number. Most importantly, it is found that from N=6 to 13, the spin moment is 8μB in all cases, which verifies the quantum confinement of 4s electrons in small nickel clusters.