Beta Decay Studies Of Neutron-Rich Nuclides Near N = 32

摘要

We report on the low-energy structure of the neutron-rich, even-even nuclides ~(54)Ti_(32), ~(56)Cr_(32), and ~(58)Cr_(34) studied via β-delayed γ-ray spectroscopy. The systematic variation of the excitation energy of first excited 2~+ states in the even-even _(24)Cr and _(22)Ti isotopes provides evidence of a subshell closure at N = 32 for neutron-rich nuclides having Z ≤ 24. Shell model calculations, which correctly account for the appearance of the N = 32 subshell, also predict a new shell closure at N = 34 for Ti and Ca isotopes.