Spectroscopy of neutron-unbound F-27,F-28
The ground state of F-28 has been observed as an unbound resonance 220 keV above the ground state of F-27. A comparison of this result with USDA/USDB shell model predictions leads to the conclusion that the F-28 ground state is primarily dominated by sd-shell configurations. Here we present a detailed report on the experiment in which the ground state resonance of F-28 was first observed. Additionally, we report the first observation of a neutron-unbound excited state in F-27 at an excitation energy of 2500(220) keV.
Christian, G., N. Frank, S. Ash, T. Baumann, Paul A. DeYoung, J. E. Finck, A. Gade, G. F. Grinyer, B. Luther, M. Mosby, J. K. Smith, J. Snyder, A. Spyrou, M. J. Strongman, M. Thoennessen, M. Warren, D. Weisshaar and A. Wersal. "Spectroscopy of Neutron-Unbound F-27,F-28." Physical Review C 85, no. 3.00 (2012).