Configuration mixing effects in neutron-rich carbon isotopes

Abstract

Shell model calculations are done to study the structure of neutron-rich carbon isotopes. For both even-A and odd-A neutron-rich carbon isotopes, the energy levels are strongly affected by the configuration mixing of valence neutrons. The calculated energy levels in the nucleus ${}^{17}$C are significantly improved compared with experimental values when the model space of the three valence neutrons is enlarged from pure $\nu (0d_{5/2}{)}^3$ configuration to full $sd$ space. We also investigate the configuration mixing effect on the $B(E2)$ values in even-even nuclei ${}^{16-20}$C.