Shell-model calculations on the nickel isotopes

Abstract

Binding and excitation energies, electromagnetic transition rates and multipole moments have been calculated for 57–66Ni from many-particle shell-model wave functions with neutrons in the 2 p 3 2 , 1 f 5 2 and 2 p 1 2 orbits outside the 56Ni core. The efiective two-body matrix elements are obtained from the modified surface delta interaction. The average absolute deviation between the calculated and experimental binding and excitation energies is 0.11 MeV (with the exclusion of 66Ni). Electric quadrupole transition rates and moments are calculated with an effective neutron charge e n = (1.70±0.08) e, obtained from a least-squares fit to experimental data. Magnetic dipole transition rates and moments follow from five fitted effective reduced singleparticle matrix elements. The average absolute deviations between theory and experiment for the strongest E2 transitions (1–15 W.u.) and for the strongest M1 transitions (0.01–0.14 W.u.) are 3.5 and 0.03 W.u., while the average measured strengths are 7.0 and 0.07 W.u., respectively.