Cold fission as heavy ion emission

Abstract

The last version of the analytical superasymmetric fission model is applied to study cold fission processes. Strong shell effects are present either in one or both fission fragments. A smooth behaviour is observed when the proton or the neutron numbers are changed by four units. IncreasingZ andN, in the transuranium region, a sharp transition from asymmetry with a large peak-to-valley ratio to symmetry atZ=100 and/orN=164 is obtained. The transition toward asymmetry at higherZ andN is much smoother. The most probable cold fission light fragments from234U,236U,239Np and240Pu are100Zr,104Mo,106Mo and106Mo, respectively, in good agreement with experimental data. The unified treatment of alpha decay, heavy ion radioactivities and cold fission is illustrated for234U — the first nucleus in which all three groups have been already observed.