Distinction between pre-formed cluster emission and heavy ion decay by fission

For studying cluster radioactivity in the actinide region as well as trans- tin region two types of models are used: the pre-cluster formation model an d the unified fission model. In the case of the actinide region, the cluste r-like shapes are preferred for very high asymmetry while fissioning shapes are more suitable for less asymmetry and symmetry (the line of demarcation being around A(e) = 31). In this work this line of demarcation is studied in the case of the trans-tin region. The results of this study show that th e transition from cluster mode to fission mode takes place at A(e) = 16.