Multiparticle-multihole states in 31Mg and 33Mg: A critical evaluation

Abstract

The experiments that provide information about the level structure of the "island of inversion" isotopes 31Mg and 33Mg are reviewed. Since the model-independent measurement of their ground-state spins was done, much experimental data can be reinterpreted, and spins and parities can be assigned to their excited states. Both experimental level schemes are found in very good agreement with calculations based on antisymmetrized molecular dynamics combined with the generator coordinate method. These calculations predict that both ground states are dominated by 2ω neutron excitations (more than 85% of the wave function). In the case of 33Mg, the energy of the 1ω and 3ω levels are calculated about 400 keV too high with respect to the ground state, while in 31Mg the 1ω levels are calculated only 200 keV too high. New key experiments are suggested. © 2011 American Physical Society.