ИСТИНА

The evolution of neutron single-particle characteristics of isotones with N = 14, 16 was studied in the dispersive optical model [1] in Z region from 7 to 20. The calculation was performed with the parameters both extrapolated in accordance with the global parameters KD (KDUQ) [2, 3] and with the diffuseness parameter aHF depending on the neutron excess. With an increase in the neutron excess, the energy gap N = 14 and N = 16 is reduced and widens respectively. In addition, the deviation DF = |<E1d5/2 ,E2s1/2> EF | of the middle between the 1d5/2 and 2s1/2 energies from the Fermi energy EF increases for N = 14 isotones. It reflects the disappearance of N = 14 magicity when approaching the neutron drip line. While, the deviation DF = |<E2s1/2 ,E1d3/2> EF | for isotones with N = 16 decreases. An increase in the aHF parameter for unstable isotones enhances this effect. The obtained results are consistent with the double magicity of 24O (N = 16) and 34Ca (N = 14) nuclei. As an example, Fig. 1 shows the evolution of neutron single-particle energies Enlj near the Fermi energy of isotones with N = 14. The deviation DF is represented relative to the value of particle-hole energy gap G.