Shell model treatment of the structure of light neutron-rich nuclei

The structure of 1p-shell nuclei, including the neutron-rich 11Be and 11Li, are studied within the shell model. The structure of nuclei near the β-stability line can be well described. In contrast, using standard parameters for the residual interaction, a number of features of nuclei far from β-stability, as for example the properties of the ground state of 11Be, are not reproduced by the shell model. More than 20 experimental level data of nuclei far from β-stability are then selected to determine new effective parameters for the modified surface delta interaction and for the single-particle energies. With these parameters used in the calculation for the 1p-shell nuclei far from β-stability, the agreement between computed results and experimental data becomes fair, and the parity inversion for the 1/2+ ground state in 11Be is correctly reproduced. The results suggest that the shell model with a proper modification of the parameters in the modified surface delta interaction can be used usefully in the description of the structure of exotic nuclei. (author)