Impact of off-diagonal cross-shell interaction on 14 C

The shell-model investigation is performed to show the impact on the structure of ¹⁴C contributed by the off-diagonal cross-shell interaction, ppVsdsd, which represents the mixing between the $0$ and 2ω configurations in the $psd$ model space. Observed levels of the positive states in ¹⁴C can be nicely described in 0-4ω or a larger model space through the well defined Hamiltonians, YSOX and WBP, with a reduction on the strength of the ppVsdsd interaction in the latter. The observed B(GT) values for ¹⁴C can be generally described by YSOX, while WBP and their modifications on the ppVsdsd interaction fail for some values. Further investigation shows the effect of such interaction on the configuration mixing and occupancy. The present work shows examples on how the off-diagonal cross-shell interaction strongly drives the nuclear structure.