The Effect of Proton-Neutron Interactions on Energy Spectra of Nuclei of A\simeq120–145

Abstract

The location of neutron-single hole states 2d_3⁄2, 3s_1⁄2, 1h_11⁄2 and 2d_5⁄2 in neutron magic N=82 nuclei ¹³⁶Xe, ¹³⁸Ba, ¹⁴⁰Ce, ¹⁴²Nd and ¹⁴⁴Sm is studied on the basis of proton-neutron interactions. The observed variations of the neutron-single hole energies of 2d_3⁄2, 1h_11⁄2 and 2d_5⁄2 states relative to that of the 3s_1⁄2 state in going from ¹³⁵Xe to ¹⁴³Sm are reproduced fairly well by the use of an interaction V_pn=(V₀+V₁σ_p·σ_n)δ(r_p−r_n) and of harmonic oscillator wave functions. The proton configurations which have been obtained from proton-transfer reactions on these isotones are employed in the calculations. Also the dominant features of the neutron-state structures and the proton-state structures observed in N=82 isotones and Z=50 isotopes are discussed from the standpoint of the proton-neutron interactions.