The self-organized localized structures in a medium pressure annular rf glow discharge are investigated. Clusters with different number of ionization clumps are observed through inversed bifurcation processes after the onset of the periodic crystal-like structure. The interaction between clusters is long range repulsive, and short range attractive before reaching the center highly repulsive core. The scattering and the formation of the stable and metastable larger clusters through the collision between two clusters are demonstrated.
