On the Origin of Nuclear Clustering

Clustering is one of the most complex phenomena known to thestructure of atomic nuclei. A comprehensive description of this ubiquitous phenomenon goes beyond standard shell model and cluster model frameworks. We argue that clustering is a consequence of an openness of the nuclear many-body system, which leads to the collectivization of Shell Model (SM) states. To illustrate this point, we study the collective mixing of J = 0^+ SM states due to the coupling to a common ℓ = 0 proton decay channel in ^{16}Ne and ^{24}S. We show that the energy of maximal collective coupling of SM eigenstates depends mainly on the Coulomb barrier; hence, the discussion also pertains to situations involving complex clusters.