Alpha decay from fission isomeric states

Alpha-decay half-lives from shape isomeric states of some even-even isotopes of U, Pu and Cm nuclei are calculated by using fission theory in the parametrisation of a spheroid intersected with a sphere. The potential barrier was calculated in the framework of the liquid-drop model of Myers and Swiatecki (1967) extended for systems with different charge densities; a phenomenological shell correction was introduced. The WKB computed lifetimes are many orders of magnitude longer than that of the spontaneous fission process, in agreement with experimental results.