Effective nucleon-nucleon interactions in the nuclei with 29 and 30 neutrons

Abstract

The energy levels of the nuclei with 20 ≦ Z ≦ 28, N = 29 and 30 are first calculated under the assumptions that their protons and neutrons outside Z = 20 and N = 28 are in the 1 f 7 2 and 2 p 3 2 orbits, respectively, and that the effective nucleon-nucleon interactions are given by the experimental spectra of the nuclei with the same Z but N = 28, of 56Co and 58Co. Qualitative agreement with experiment is generally achieved for energy level positions, ground state binding energies, magnetic and quadrupole moments, reduced M1 and E2 transition probabilities and spectroscopic factors for nucleon transfer reactions. The influence of configuration admixtures involving the 2 p 1 2 and 1 f 5 2 neutron orbits on the nuclei with 29 neutrons is then investigated; the effective proton-neutron interaction is assumed to have a δ-function radial dependence and its strength and spin contribution are determined both from the previous analysis and from the motion of the 2 p 1 2 and 1 f 5 2 neutron orbits with respect to 2 p 3 2 between 49Ca and 57Ni. Satisfactory quantitative agreement with experiment is obtained for energy level positions, spectroscopic factors for the (d, p) reaction on the nuclei with 28 neutrons, magnetic moments and reduced M1 transition probabilities, and, only qualitatively, for β-decay data