*3.2. Neutron Shell Evolution*

In this Subsection, the neutron shells that change with the proton number are considered, as illustrated in Figure 2b. Let us start with the 48Ca core, since its neutron *p f*-shell energies are well established from the data. Next, the protons are removed from the *d*3/2, *s*1/2, and *d*5/2 orbitals, and the relevant issues are discussed in Sections 3.2.1 to 3.2.3, respectively.
