Decay of spontaneous fission isomers in the coulomb field of a third nucleus

In the framework of trinuclear system (TNS) model, we investigate the formation of heavy fission isomers produced in spontaneous ternary fission of [Formula: see text]Cf, and their decay while traversing the Cu foil, observed in Dubna experiments. After the first decay of TNS, the asymmetric DNS is formed introducing itself as a fission isomer in cluster state. The Coulomb interaction of this asymmetric DNS and foil nucleus Cu decreases the DNS decay barrier. The calculated half-lives of asymmetric DNS show a strong decrease when the DNS approaches to the foil nucleus Cu, supporting the experimental observations.