Shell model description of the core excited level structure of $$^{89}$$Sr nucleus and systematic features of the $$N=51$$ odd-A isotones

Abstract

Shell-model calculations are performed using NuShellX code in the model space $$\pi $$($$f_{5/2}$$, $$p_{3/2}$$, $$p_{1/2}$$, $$g_{9/2}$$) $$\otimes $$ $$\nu $$($$g_{9/2}$$, $$g_{7/2}$$, $$d_{5/2}$$, $$h_{11/2}$$), which probe the proton core excitation from the interior of $$Z=38$$ semiclosed shell and neutron core excitation from the interior of $$N=56$$ semiclosed shell for the level structure of $$^{89}$$Sr. Our calculations show that the excitation of a single $$d_{5/2}$$ neutron across $$N=56$$ semiclosed shell into the $$h_{11/2}$$ orbit should have great effects on the excited states of $$^{89}$$Sr. In addition, the systematic features of proton core excitation across $$Z=38$$ semiclosed shell into the $$g_{9/2}$$ orbit and neutron core excitation across $$N=56$$ semiclosed shell into the $$g_{7/2}$$, $$s_{1/2}$$, $$d_{3/2}$$, $$h_{11/2}$$ orbits in $$N=51$$ isotones are discussed.