WEAKLY BOUND STRUCTURES, HALOS AND MAGICITY IN NEUTRON RICH NUCLEI

Inspired by recent measurements indicating proton magic number at Z=14 in the vicinity of ⁴²Si, we have employed our relativistic mean-field (RMF) plus state dependent BCS approach for the study of even-even nuclei to obtain magic numbers and to look for nuclei exhibiting weakly bound structures and even halo formation. In our RMF+BCS approach the single particle continuum corresponding to the RMF is replaced by a set of discrete positive energy states for the calculations of pairing energy. It is found that in several nuclei the filling in of low lying single particle resonant state with large angular momentum, even before it becomes a bound state, helps to accommodate more neutrons but with extremely small increase in the binding energy. This gives rise to the occurrence of weakly bound system of neutron rich nuclei.