Shell-model study of the calcium isotopes (A = 42 to 48) using a pairing-plus-surface-tensor interaction

The calcium isotopes ⁴²Ca through ⁴⁸Ca are described within the framework of the conventional shell model using a phenomenological effective two-body interaction. The residual interaction consists of usual j-j pairing plus a surface-tensor force. ⁴⁰Ca is assumed to be an inert core. Besides all possible configurations arising from 1f_7/2 and 2p_3/2 orbits, configurations of the form (1f_7/2)ⁿ¹(1f_5/2)ⁿ² where n₁+n₂=n (the number of extracore neutrons) and n₂=1, 2, are also considered in the basis vector spaces. The calculated ground-state energies as well as the excited energy levels are in good agreement with the experimental values. Reproduction of single-neutron spectroscopic factors for stripping and pickup reactions is also good.