The relativistic density functional investigations on geometries, electronic and magnetic properties of Irn (n=1-13) clusters

The Ir_n (n=1--13) clusters are studied using the relativistic density functional method with generalized gradient approximation. A series of low-lying structures with different spin multiplicities have been considered. It is found that all the lowest-energy Ir_n (n=4--13) geometries prefer non-compact structures rather than compact structure growth pattern. And the cube structure is a very stable cell for the lowest-energy Ir_n (n > 8) clusters. The second-order difference of energy, the vertical ionization potentials, the electron affinities and the atomic average magnetic moments for the lowest-energy Ir_n geometries all show odd--even alternative behaviours.