Themes

1. Binding energies, density distributions and mean square radii
2. Energies and wave functions/transition densities of the excited states, as well as electromagnetic transition probabilities to the ground state
3. Calculations of charge-changing transitions
4. Beta-decay half-lives

Computer codes for themes 1 and 2

Atomic nuclei have a very rich variety of excitation spectra ranging from elementary excitations of single-particle nature to completely collective modes like rotational motion where the entire nucleus participates as a whole. The vibrational collective modes constitute a typical example of coherent behavior of a spherical nucleus, where the excited states are built out of a constructive superposition of elementary particle-hole excitations, which results in a state largely shifted from the energy region of those elementary excitations, with a considerably increased strength. Well-known examples are the low-lying vibrations and the high-lying giant resonances which are the objects of many theoretical and experimental investigations.

The codes at hand find the spherical ground state of spherical nuclei, with the associated densities, radii and binding energy, using Skyrme energy functionals. On top of this they calculate the vibrational excitations of given angular momentum and parity.

skyrme_rpa

The code solves the Hartree-Fock equations with an effective Skyrme interaction, allowing the calculation of the properties of the ground state of even-even, spherical nuclei. Pairing correlations are neglected. The code should be run for closed shells or sub-shells. The code also solves the Random Phase Approximation equations fully self-consistently with the same interaction, calculating the excitation spectrum for natural parity states and the intensity of the electromagnetic transitions to the ground state.

G. Colò et al., Comp. Phys. Comm. 184, 142 (2013)

hfbcs_qrpa

This code extends the previous calculations including pairing correlations, giving access to the properties of open shell, spherical nuclei. It can be run for even-even nuclei with any number of nucleons. It solves the Hartree-Fock-Bardeen-Cooper-Schrieffer (HF-BCS) equations for the ground state, and the Quasiparticle Random Phase Approximation (QRPA) for the excited states.

G. Colò and X. Roca-Maza, arXiv:2102.06562 [nucl-th]

Kshell code

This code allows performing nuclear shell-model calculations. It considers as a reference core the doubly closed-shell nucleus closest to the selected system and uses as valence space for protons and/or neutrons one major shell. It provides energy levels, occupation numbers, configurations, and, if requested, E2 and M1 electromagnetic transitions, for each of the states for the selected nucleus.

N.Shimizu, T. Mizusaki, T. Utsuno, and Y. Tsunoda, Comp. Phys. Comm. 244, 372 (2019)