In exotic decay studies, the branching ratios for spontaneous emissions of fragments heavier than alpha particle have been found to be very sensitive to the shape of the potential barrier. In order to fix the top of barrier correctly, finite range effects are included in our calculations. Experimental Q values for different decay modes are chosen so as to incorporate the shell effects. The shape of the barrier in the overlapping region is approximated by a third-order polynomial suggested by Nix. The cubic barrier is found to be more suitable near the penetrating region. This model is applied to calculate the branching ratios for the spontaneous emission of heavier fragments. The results obtained compare well with those of other theoretical models and experimental values.

• Received 5 February 1987

DOI:https://doi.org/10.1103/PhysRevC.38.1377