Shell-model studies of mass-45 nuclei and calcium isotopes A=46-50: energy spectra and electromagnetic moments

Abstract

Shell-model calculations have been performed for the mass-45 nuclides 45Ti, 45Sc and 45Ca and the calcium isotopes 46-50Ca. The one-body part of the Hamiltonian was extracted from the experimental spectra of 41Ca and 41Sc whilst the two-body part used was a modification of the interaction constructed by T.T.S. Kuo and G.C. Brown (1968) from the Hamada-Johnston nucleon-nucleon potential. All Pauli-allowed pf-shell configurations were included in the model space. Magnetic dipole and electric quadrupole moments were calculated from the shell-model wavefunctions using effective operators. Comparison with experimental data shows that the Kuo-Brown interaction is moderately successful for 45Sc and 45Ti, but that the quality of the fit to energy spectra deteriorates as the number of active neutrons increases, especially for those excited states for which p3/2 configurations are important. A modification to the Kuo-Brown interaction is suggested which significantly improves the agreement achieved.