Structure studies of excited states of 17C and 16C

Abstract

The structure of excited states of 17C has been studied using the three-neutron transfer reaction 14C(12C, 9C)17C at 231 MeV. Thirteen states above the neutron threshold up to 16.3 MeV excitation energy are observed. The large negative reaction Q-value of Q0 = −46.930 MeV leads to a strong mismatch between entrance and exit channels. In this case the population of stretched configurations is strongly favoured. The lowest-lying 9/2+ state could be identified at 3.10 MeV, in excellent agreement with shell model calculations. Further tentative assignments could be given for several other states. A striking agreement is observed between excitation energies of 17C and those states of 16C populated in the 13C(12C, 9C)16C reaction, when the level schemes of both nuclei are aligned along the 9/2+ state at 3.10 MeV in 17C and the [9/2+ ⊗ 1/2−]5− state at 8.92 MeV in 16C. Deviations between Ex(17C) and the difference Ex(16C) − 5.82 stay within the range of +0.14/ −0.17 MeV for ten pairs of states of these isotopes.