Remarks on the fission barriers of super-heavy nuclei

. Shell-correction energies of super-heavy nuclei are approximated by using Q_α values of measured decay chains. Five decay chains were analyzed, which start at the isotopes 285 Fl, 294 118, 291 Lv, 292 Lv and 293 Lv. 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.