New nuclear decay modes by spontaneous and beta-enhanced emission of heavy ions

The analytical variant of the superasymmetric fussion model (ASAFM) is improved to include shell effects in the zero point vibration energy. In this way better agreement with experimental half-lives for 380 β emitters, 14C radioactivity of 222Ra and the spontaneous fission of uranium isotopes is obtained. The lifetimes of trans-lead nuclides in the range 1010-1030s are estimated for more than 150 emitted heavy ions with atomic numbers smaller than 25. The shell structure and the oddeven effects are cleary manifested in these new decay modes. One way to enhance the emission rates for these processes is to use α-decaying precursors populating excited levels from which quantum mechanical tunneling goes faster. (authors)