Evolution of single-particle structure of silicon isotopes

Abstract.New data on proton and neutron single-particle energies $ E_{nlj}$Enlj of Si isotopes with neutron number N from 12 to 28 as well as occupation probabilities $ N_{nlj}$Nnlj of single-particle states of stable isotopes 28, 30Si near the Fermi energy were obtained by the joint evaluation of the stripping and pick-up reaction data and excited state decay schemes of neighboring nuclei. The evaluated data indicate the following features of single-particle structure evolution: persistence of Z = 14 subshell closure with N increase, the new magicity of the number N = 16, and the conservation of the magic properties of the number N = 20 in Si isotopic chain. The features were described by the dispersive optical model. The calculation also predicts the weakening of N = 28 shell closure and demonstrates evolution of a bubble-like structure of the proton density distributions in neutron-rich Si isotopes.