Quasi-particle structure of proton–hole cobalt isotopes

Projected Shell Model calculations have been employed for the description of the ground band in odd mass 57–67Co isotopes. In the present work, quadrupole and monopole pairing interactions as well as quadrupole–quadrupole interactions are effectively included in the Hamiltonian for obtaining various nuclear structure properties using the angular momentum projection technique. The yrast spectra of these isotopes are described as interplay between the angular momentum projected states around the Fermi level. The quasi-particle structure of these nuclei is found to be comprised of different intrinsic K-quantum numbers. Rotational alignments in terms of kinetic moment of inertia (ℑ(1)ℑ(1)) have also been discussed. The electromagnetic transition probabilities [B(E2)B(E2) and B(M1)B(M1)] are also obtained in the present work and are found to be in good agreement with the available experimental as well as the other theoretical data, which tests the consistency of the applied projected shell model. The present PSM calculations also report the existence of low lying deformed structure along with the spherical structure at N=40N=40.