“Structure of odd scandium isotopes - properties of low spin structure in 45Sc studied by means of Coulomb excitation”

by Dr Magdalena Matejska-Minda (IFJ PAN)

Monday 24 May 2021, 14:00 → 16:00 Europe/Warsaw

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Nuclei with an excess or deficiency of neutrons with respect to the doubly magic isotopes are an effective laboratory to understand the role of the various components of the nuclear Hamiltonian. The 45Sc nucleus, situated in the nuclear chart above the doubly magic 40Ca, has 1 additional proton and 4 neutrons beyond the N = Z = 20 shell closure. Odd‑mass nuclei in the lower part of the f7/2 shell provide striking examples of non-closure effects of the N = Z = 20 shells, which result in the occurrence of many low-lying positive parity “intruder” states. The structure of odd-mass Sc isotopes is particularly interesting because of the coexistence of positive-parity and negative-parity bands near the ground state. For example, 45Sc has a degenerated 3/2+ positive-parity state only 12.4 keV above the 7/2- ground state. This isomeric state has a positive quadrupole moment and is a band-head of a rotational band developed at higher spins.

The electromagnetic structure of 45Sc at low excitation energy was investigated via low-energy Coulomb excitation. The data have been collected at the Heavy Ion Laboratory University of Warsaw and the Inter-University Accelerator Centre, New Delhi, India. From the collected data using the Coulomb excitation least-squares fitting code GOSIA a set of reduced E2, E3, and M1 matrix elements were extracted. In addition, the B(E2) value for the transition depopulating 11/2- state at 1237 keV allowed to determine the lifetime of this state.

In this talk, the electromagnetic properties of 45Sc will be discussed in the framework of large-scale mean-field theory and shell-model calculations with the ZBM2 interaction, with a particular focus on the collective properties of the observed states.

Matejska-Minda_NO2_Seminar.pdf