Spectroscopy of ${}^{21}$F with the $(\alpha$,${}^2$He) reaction

The ${}^{19}$F$(\alpha$,${}^2$He)${}^{21}$F reaction was investigated at 55 MeV incident energy. The transferred angular momenta of prominent transitions excited were determined from a distorted wave Born analysis of the angular distributions. Tentative spin assignments for the observed levels are extracted from shell-model calculations with the “unified” $\mathrm{sd}$-space interaction based on the very good reproduction of the excitation energies and the predicted large two-neutron transfer spectroscopic factors.