Microscopic model for the collective enhancement of nuclear level densities

Abstract

A microscopic method for calculating nuclear level densities (NLD) is developed, based on the framework of energy density functionals. Intrinsic level densities are computed from single-quasiparticle spectra obtained in a finite-temperature self-consistent mean-field (SCMF) calculation that takes into account nuclear deformation, and is specified by the choice of the energy density functional (EDF) and pairing interaction. The total level density is calculated by convoluting the intrinsic density with the corresponding collective level density, determined by the eigenstates of a five-dimensional quadrupole or quadrupole plus octupole collective Hamiltonian. The parameters of the Hamiltonian (inertia parameters, collective potential) are consistently determined by deformation-constrained SCMF calculations using the same EDF and pairing interaction. The model is applied in the calculation of NLD of ${}^{94,96,98}$Mo, ${}^{106,108}$Pd, ${}^{106,112}$Cd, ${}^{160,162,164}$Dy, ${}^{166}$Er, and ${}^{170,172}$Yb, in comparison with available data. It is shown that the collective enhancement of the intrinsic level density, consistently computed from the eigenstates of the corresponding collective Hamiltonian, leads to total NLDs that are in excellent agreement with data over the whole energy range of measured values.

arXiv comment9 pages, 7 figures

References in corpus (29)

• Relativistic Continuum Hartree Bogoliubov Theory for Ground State Properties of Exotic Nuclei
• Relativistic Nuclear Energy Density Functionals: adjusting parameters to binding energies
• A finite range pairing force for density functional theory in superfluid nuclei
• Beyond the relativistic mean-field approximation (III): collective Hamiltonian in five dimensions
• Spontaneous fission modes and lifetimes of super-heavy elements in the nuclear density functional theory
• Potential Energy Surfaces of Actinide Nuclei from a Multi-dimensional Constraint Covariant Density Functional Theory: Barrier Heights and Saddle Point Shapes
• Multidimensionally-constrained relativistic mean field models and potential energy surfaces of actinide nuclei
• Critical temperature for quenching of pair correlations
• Multidimensionally-constrained covariant density functional theories --- nuclear shapes and potential energy surfaces
• Pairing-induced speedup of nuclear spontaneous fission
• Spin projection in the shell model Monte Carlo method and the spin distribution of nuclear level densities
• Particle-Number Reprojection in the Shell Model Monte Carlo Method: Application to Nuclear Level Densities
• Multidimensionally-constrained relativistic mean-field study of spontaneous fission: coupling between shape and pairing degrees of freedom
• Spontaneous fission lifetimes from the minimization of self-consistent collective action
• Thermal properties and radiative strengths in 160,161,162Dy
• Simultaneous quadrupole and octupole shape phase transitions in Thorium
• Thermal and electromagnetic properties of 166-Er and 167-Er
• Microscopic self-consistent description of induced fission dynamics: finite temperature effects
• Coexistence of nuclear shapes: self-consistent mean-field and beyond
• Transitional $\gamma$ strength in Cd isotopes
• Pairing transitions in the finite-temperature relativistic Hartree-Bogoliubov theory
• Tetrahedral shapes of neutron-rich Zr isotopes from multidimensionally-constrained relativistic Hartree-Bogoliubov model
• Level densities and $\gamma$-ray strength functions in ${}^{170,171,172}$Yb
• Time-dependent generator coordinate method study of mass-asymmetric fission of actinides
• A High-Performance Algorithm to Calculate Spin- and Parity-Dependent Nuclear Level Densities
• Stochastic Estimation of Nuclear Level Density in the Nuclear Shell Model: An Application to Parity-Dependent Level Density in ${}^{58}$Ni
• Shape transition with temperature of the pear-shaped nuclei in covariant density functional theory
• Microscopic calculations of nuclear level densities with the Lanczos method
• Collective inertia and fission barriers within the Skyrme-Hartree-Fock theory

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