Fusion reactions and synthesis of some superheavy nuclei
Résumé
The potential barriers standing against the formation of some superheavy nuclei have been studied within a Generalized Liquid Drop Model taking into account the proximity forces acting between surfaces in regard, the charge and mass asymmetry, the shell and pairing effects and an adjustment to reproduce the experimental or predicted Q value. Quasimolecular shapes leading from two spheres to one sphere have been used. In very asymmetric entrance channels one hump potential barrier stands and might lead to very excited nuclei cooling by neutron or α particle evaporation. For less asymmetric reactions double hump potential barriers appear and quasifission or alpha decay of compact and creviced one-body shapes may occur in the external well beside fusion-fission events in the first inner well. For almost symmetric reactions there is no more external barrier but rather a continuous climb till the sphere. Predictions of alpha decay half-lives of the studied superheavy nuclei are given using a recently proposed formula.