In the neutron-rich sd shell near the N = 20 'island of inversion', the evolution of the N = 20 shell gap is indicated by the energies of negative-parity states which primarily arise due to single neutron excitation to higher lying orbitals across the shell gap. These negative-parity states often have high spin (due to the participation of the 0f7/2 orbital) and are therefore preferentially populated using fusion-evaporation reactions. We have studied the intermediate energy levels of 32Si and 29Al using 12C(22Ne,2p) and 12C(22Ne,alpha p) reactions, identifying several negative-parity states in both nuclides.
QC 20250311