Coupling between fragment radial motion and the transversal degrees of freedom in cold fission

The tunneling of a quasibound dinuclear system along the main radial mode is studied for the case of cold fission when the very small excitation energy present in the decaying system is distributed among molecular type transversal collective degrees of freedom. Such a collective mode has typical oscillation periods much smaller than the tunneling time of the main radial mode and, therefore, we discuss various approaches that are suitable in dealing with this problem. The modified penetrabilities are obtained at first by solving the coupled set of Schrödinger equations in the adiabatic and the diabatic approximations. The comparison with the one-dimensional penetrability is done also in the frame of the Feynman path integral formalism for a very large inertial mass and small transversal vibrations frequency. In all cases the coupling of the radial(fission) mode to the transversal degrees of freedom leads to a change in the tunneling probability that is, however, not so strong to determine significant variations in the fission lifetime.