Theoretical description of cold fission modes

In the spontaneous fission of 252 Cf two or more fragments emerge from the reaction. A limiting case of this process is represented by the so-called cold fission in which the decay products have very low excitation energy, in any case bellow the neutron emission threshold. The close resemblance between this phenomenon and the cluster radioactivity prompted the investigation of the cold fission from the standpoint of a cluster model with fragments deformations taken into account. This model describes the cold fission as the decay of a quasi-bound giant nuclear aggregate (molecule) or dinuclear system, the fragments being in their ground states with quadrupole, octupole and hexadecapole deformations. The interaction between the fragments is simply the sum of nuclear and Coulomb contributions. In the articles that our group published in last years, we took in the description of 252 Cf cold fission, the M3Y and Migdal interaction for the nuclear part. We outline the applications of this model to several channels of cold fission occurring in 252 Cf. Topics like calculation of the half-lives of the alpha-like trinuclear molecules, the preformation of light clusters on the surface of the hyperdeformed mother nucleus, the collective modes for the 10 Be-like trinuclear molecules and the shift of the first 2+ state of 10 Be in the quasi-molecular configuration are discussed. (author)