Isotopic features of the N p N n function for even-even isotope chains of Ni and Zn

Low-energy (0.04–3.0 MeV) neutron data for even-even ^58–64Ni and ^64–70Zn isotopes are analyzed in terms of the coupled channel optical model (CCOM) as a function of N _p N _n, where N _p(N _n) are the numbers of valent nucleons (particles or holes), and consider the relationship between the diffuseness parameter obtained from CCOM calculations and the value of the N _p N _n function. Considering the Ni and Zn isotope chains with the traditional magic number Z = 28 and the nontraditional N = 38 proves the existence of N = 28–38 subshells. The results from our analysis indicate the possible existence of the nontraditional magic nucleus ₃₀ ⁶⁸ Zn₃₈.