Phys.Rev. C 106, 044313 (2022)

D.Little, A.D.Ayangeakaa, R.V.F.Janssens, S.Zhu, Y.Tsunoda, T.Otsuka, B.A.Brown, M.P.Carpenter, A.Gade, D.Rhodes, C.R.Hoffman, F.G.Kondev, T.Lauritsen, D.Seweryniak, J.Wu, J.Henderson, C.Y.Wu, P.Chowdhury, P.C.Bender, A.M.Forney, W.B.Walters

Multistep Coulomb excitation of ⁶⁴Ni: Shape coexistence and nature of low-spin excitations

NUCLEAR REACTIONS ²⁰⁸Pb(⁶⁴Ni, ⁶⁴Ni'), E=272 MeV; measured reaction products, time-of-flight difference between the projectile and target recoils as a function of scattering angle, Eγ, Iγ, (particle)γ-coin, Coulomb-excitation yields using GRETINA array with 12 modules of 48 highly-segmented coaxial HPGe crystals for γ detection, and CHICO2 array of 20 position-sensitive parallel-plate avalanche counters for the detection of scattered particles at the ATLAS-ANL facility. Multistep safe Coulomb-excitation. ⁶⁴Ni; deduced levels, J, π, E2 matrix elements using GOSIA least-squares fitting code, B(E2), spectroscopic electric quadrupole moments, evidence for triple shape coexistence. Comparison with previous experimental results, and with Monte Carlo shell-model (MCSM), and conventional shell-model calculations.

NUCLEAR STRUCTURE ⁶⁴Ni; calculated levels, J, π, B(E2), spectroscopic quadrupole moments, proton and neutron orbital occupancies for 2+ and 0+ states using Monte Carlo shell-model (MCSM), and conventional shell-model calculations with the jj44 and fp effective interactions. Comparison with experimental data.

doi: 10.1103/PhysRevC.106.044313