Fission dynamics within time-dependent Hartree-Fock: deformation-induced fission

Studies of nuclear fission have been ongoing since the discovery of the process in 1938 by Hahn and Strassmann [1]. The actinide nuclide Pu has long been a case of interest, as spontaneous fission presents itself as a decay mechanism with significant probability, relative to other isotopes in the actinide region. This allows for quantitative comparisons between spontaneous and induced fission [2–5]. Experimentally, fission can be induced by a variety of techniques, including neutron-induced fission, fission induced by more complex projectiles, and photofission [2, 6]. Recent experimental campaigns have investigated β-delayed fission [7]. Theoretically, microscopic studies have focused upon the role of the quadrupole degree of freedom in forming the fission pathway, as exemplified by constrained meanfield calculations [8, 9]. The typical observed behaviour in actinide nuclei for the binding energy as a function of increasing quadrupole deformation is to follow a multihumped pathway (see Fig. 1). When considering the potential energy surface (PES), starting from the ground state, then increasing the quadrupole deformation will result in a first fission barrier. By increasing the deformation further, a secondary minimum, corresponding to an isomer, is found. Beyond this minimum, a second fission barrier is encountered, and past this barrier, the general consensus is that it becomes more energetically favourable for the nucleus to fission. The energies EA, EB and EII presented in Fig. 1 correspond to