Secondary fission barriers in even-even actinide nuclei

Secondary fission barriers are calculated within the macroscopic-microscopic model in six-dimensional deformation space for even-even actinides. No special adjustable parameters are used. To search for saddle points, the ``immersion'' method is applied on a giant six-dimensional grid. This approach leads to a good agreement with (small deviation from) the available experimental data. Moreover, it is consistent with the other saddle-point searching technique. The influence of the incorporated nonaxiality on second fission barriers is found to be negligible, in contrast with the well-known major effect of the reflection asymmetry.