Structure of Fission Potential Energy Surfaces in Ten-Dimensional Spaces

Observed features of the fission process could be explained with the help of calculated multi-dimensional potential energy surfaces (PES). The energy minima positions in multi-dimensional deformation space reflect the nuclear shape evolution from ground state through intermediate stages to final configuration of separated fission fragments. An increase in accuracy of PES calculations is achieved by choosing the non-restricted shape parameterization. The importance of sufficiently large and complete deformation space in PES calculations has been discussed in [ 1, 21. In case of low energy fission, the coherent motion of the nucleus can be described by means of a several collective parameters characterizing the shape of the system. Consequently, the internal structure of nucleus can be assumed to be in equilibrium at each step of the collective motion. The internal degrees of freedom of the system can therefore be described using the adiabatic approximation. The shell-correction part [3] of the nuclear energy is responsible for the multi-modal structure of the high-dimensional PES.