CALCULATIONS OF ENERGY SPECTRA OF NUCLEI IN THE 2s, 1d SHELL

Using the shell-model classification scheme based on the group $\mathrm{SU}3$, the energy spectrum of ${\mathrm{Mg}}^{24}$ is studied in detail. Using only the lowest $\mathrm{SU}3$ state it is not possible to obtain a good fit to the experimental data. A variational method is introduced within the framework of the $\mathrm{SU}3$ scheme which admixes higher states. This yields good agreement between theory and experiment.