Electromagnetic Processes in Drip-Line Nuclei

Change of the shell structure near drip-lines is pointed out and enhancement of low-energy dipole strength is shown in light drip-line nuclei. Change of the shell magicity can be explained by taking into account an important role of spin-isospin interaction. New aspects of quenching effects in Gamow-Teller (GT) transitions and magnetic moments are investigated for p-shell nuclei using improved shell-model interactions with enhanced spin-flip neutron-proton interactions and modified single-particle energies. Manifestation of less quenching due to a weakening of intermediate coupling nature of the Cohen-Kurath interction is shown in GT transitions; ¹²C → ¹²N, ¹¹B → ¹¹Be and ⁹Li → ⁹Be. Better agreement with experimental values is obtained by using the present interactions in most of GT transitions and magnetic moments in p-shell nuclei.