Finite-amplitude method for collective inertia in spontaneous fission

Abstract

Background: Microscopic description of spontaneous fission is one of the most challenging subjects in nuclear physics. It is necessary to evaluate the collective potential and the collective inertia along a fission path for a description of quantum tunneling in spontaneous or low-energy fission. In past studies of the fission dynamics based on nuclear energy density functional (EDF) theory, the collective inertia has been evaluated with the cranking approximation, which neglects dynamical residual effects. Purpose: The purpose is to provide a reliable and efficient method to include dynamical residual effects in the collective inertia for fission dynamics. Methods: We use the local quasiparticle random-phase approximation (LQRPA) to evaluate the collective inertia along a fission path obtained by the constrained Hartree-Fock-Bogoliubov method with the Skyrme EDF. The finite-amplitude method (FAM) with a contour integration technique enables us to efficiently compute the collective inertia in a large model space. Results: We evaluate the FAM-QRPA collective inertia along a symmetric fission path in ${}^{240}$Pu and ${}^{256}$Fm. The FAM-QRPA inertia is significantly larger than the one of the cranking approximation, and shows pronounced peaks around the ground state and the fission isomer. This is due to dynamical residual effects. Conclusions: To describe the spontaneous or low-energy fission, we provide a reliable and efficient method to construct the collective inertia with dynamical residual effects that have been neglected in most of EDF-based works in the past. We show the importance of dynamical residual effects to the collective inertia. This work will be a starting point for a systematic study of fission dynamics in heavy and superheavy nuclei to microscopically describe the nuclear large-amplitude collective motions.

12 pages, 7 figures

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Cited by in corpus (17)

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• Finite amplitude method on the deformed relativistic Hartree-Bogoliubov theory in continuum: The isoscalar giant monopole resonance in exotic nuclei
• Skyrme-Hartree-Fock-Bogoliubov mass models on a 3D mesh. IIb. Fission properties of BSkG2
• Generation, dynamics, and correlations of the fission fragments' angular momenta
• Microscopic Calculation of Fission Product Yields for Odd-Mass Nuclei
• Non-iterative finite amplitude methods for E1 and M1 giant resonances
• Microscopic description of cluster decays based on the generator coordinate method
• Benchmark of many-body approaches for magnetic dipole transition strength
• QRPA calculations for M1 transitions with the noniterative finite amplitude method and the application to neutron radiative capture cross sections
• Five-dimensional collective Hamiltonian with improved inertial functions
• Evolution of giant monopole resonance with triaxial deformation
• Dipole response in deformed halo nuclei ${}^{42}\mathrm{Mg}$ and ${}^{44}\mathrm{Mg}$
• Numerical Convergence of Electromagnetic Responses with the Finite-Amplitude Method
• Microscopic Theory of Nuclear Fission
• Impact of octupole deformation on the nuclear electromagnetic response