The magicity, the radii of neutron orbits 1<i>f</i><sub>7/2</sub>, 2<i>p</i><sub>3/2</sub> and halo-like structure of <sup>52,54</sup>Ca nuclei

The evolution of neutron single-particle spectra of isotones with N = 32 and 34 new magic neutron numbers in the region 16 ≤ Z ≤ 32 was calculated in the dispersive optical model. It was shown that the minimum of the difference between the Fermi energy and the half-sum of the energy levels of the last predominantly occupied state and the first predominantly unoccupied state is achieved in the magic isotones with N = 32 and 34. The calculated root-mean-square radius of the neutron halo-like state 2p3/2 in double magic 52Ca nucleus exceeded the radius of the underlying 1f7/2 state by 0.8 fm. It is consistent with the recent experimental data and theoretical predictions that explain ‟unexpectedly” large root-mean-square charge radius of this nucleus.