Shape parametrization of fission nuclei by Cassinian ovaloids

Based on well‐defined fission shape, the Cassinian ovaloid, the PES (potential energy surface) for asymmetry fission with shell revision has been calculated. Two halves of Cassinian Ovaloids smoothly joined together are utilized as asymmetry fission shapes. Therefore there are only two collective variables needed in the approach: an eccentricity, ε1, and a mass asymmetry parameter, p; necking‐in is an inherent property of Cassinian ovaloids and does not require an additional parameter. When neck appears, the shell revision is treated to two parts of nucleus on both sides of the neck, separately. For each part there is a inner lemniscatoid as a core, which develops to whole fragment, when ε1 increases from 0.7 to 1.0. By semi‐empirical formula due to Swieatecki, the shell revision energy is calculated only on the core instead of whole fragment. Examplary results for 208Pb, 233Th and 252Cf qualitatively feature the expected properties of static fission barrier and saddle points.