Shell closures in the N and Z=40-60 region for neutron and proton-rich nuclei

A systematic study of shell closures around N and Z=40-60 through beta decay Q-values, one nucleon separation energies and excited states is presented for different isospin chains. Shell closure at N=40 is found to be absent in neutron-rich nuclei (contrary to some existing discussions) but is indicated in nuclei with Tz⩽1 within errors. The persistence of the N and Z=50 shell closure is observed, together with evidence of sub-shell closure at N=56 in neutron-rich nuclei. The sub-shell closure at Z=40, that exists for neutron-rich nuclei, is found to disappear for Tz=2.