Occupancy of orbitals and the quadrupole collectivity in 45Sc nucleus

In the present work, the Doppler Shift Attenuation method (DSAM) was used to analyze the observed lineshapes of transitions from excited states in 45Sc, populated in the reaction 36Ar + 12C at a beam energy of 145 MeV. The interpretation and comparison of the experimental results have been performed with large-scale shell model calculations, involving different interactions like: GX1A, GX1J, FPD6, KB3 and ZBM2. KB3 and FPD6 (present work) interactions in the negative parity states, and in positive parity states ZBM2 are most pre-eminent in reproducing the results, due to the large configuration space describing strong collective effects. Furthermore, the present work also looks at the details of the shell model helping in improving the understanding for the occupancy of orbitals. The present investigation suggests the observation of stronger collectivity for positive parity states over negative parity states with predicted enhanced collectivity of states in 45Sc nucleus. •The revised lifetime measurements based on Doppler Shift Attenuation Method in 45Sc populated with a non-standard C-target not only have verified the lifetimes with good accuracy but also the target’s effectiveness.•Reaction reported in the present work has suggested the highest cross section compared to the different reactions reported in the literature, and have confirmed better statistics to the results and thus the improved uncertainty.•Effect of side-feeding lifetime to the level of interest has been discussed.•Present investigation suggests the observation of stronger collectivity for positive-parity states with enhanced quadrupole coherence. The observed large collectivity and irregular energy-spacing may be considered as an evidence of either a level-crossing with consequent backbending, or alternatively as a break-down of collectivity with re-appearance of shell-model behavior.•The presented study will put forward the researchers for a better understanding of the occupancy of orbitals, and will lead to a more general but an effective shell model interaction matching the results near A∼45 mass region other than Sc and Ti nuclei.