  Large-basis shell model studies of low-lying excitations in light nuclei from
4He to 7Li have been performed with a multi-valued G-matrix effective
interaction, as recently suggested by Haxton et al.. Calculations were
performed relative to the vacuum (``no core") using very large, separable model
spaces containing all excitations with unperturbed energies up to 8\hbar\Omega.
Using G matrices derived from a new Nijmegen potential, we achieve a very
satisfactory description of these excitations.
