A theoretical study on the clusters Ir_n with n = 4, 6, 8, 10

For investigating the hydrocarbon hydrogenation catalytic activity of metal particles which become size-dependent as the particles which become so small as clusters, the clusters Ir_n with n = 4, 6, 8, 10 are studied by using effectvie core potential (10s5p3d)/[2s1p1d] basis set of Gaussian-94 program. THe calculated result shows that for spin singlet, the clusters Ir₄ and Ir₆ without solid support are of size-dependent reactivity, whereas the clusters Ir₈ and Ir₁₀ without solid support may be of size-independent reactivity, even they may not possess catalytic activity.