Fusion and Quasifission in Superheavy Element Synthesis

In the 1960s, quite soon after the recognition of the role of quantum shells in providing extra stability to nuclei, an “island of stability” of spherical superheavy nuclei was predicted. It was expected to be centered on proton number Z = 114 and neutron number N = 184, the next magic numbers predicted above Z = 82 and N = 126, which give nuclei around ²⁰⁸Pb their enhanced stability. Since then, intensive experimental efforts have been made to synthesize these superheavy elements, usually defined as those with atomic number 104 or more.