Remarks on the fission barriers of super-heavy nuclei

Shell-correction energies of super-heavy nuclei are approximated by using (Formula presented.) values of measured decay chains. Five decay chains were analyzed, which start at the isotopes ²⁸⁵Fl, ²⁹⁴118, ²⁹¹Lv, ²⁹²Lv and ²⁹³Lv. The data are compared with predictions of macroscopic-microscopic models. Fission barriers are estimated that can be used to eliminate uncertainties in partial fission half-lives and in calculations of evaporation-residue cross-sections. In that calculations, fission probability of the compound nucleus is a major factor contributing to the total cross-section. The data also provide constraints on the cross-sections of capture and quasi-fission in the entrance channel of the fusion reaction. Arguments are presented that fusion reactions for synthesis of isotopes of elements 118 and 120 may have higher cross-sections than assumed so far.