High-spin structure of $^{87}$Sr and $^{87}$Zr nuclei : shell model interpretation

Abstract

In the present work we report a comprehensive analysis of shell model results for high-spin states of $^{87}$Sr and $^{87}$Zr for recently available experimental data within the full $f_{5/2}pg_{9/2}$ model space using JUN45 and jj44b effective interactions developed for this model space. In this work we have compared the energy levels, electromagnetic transition probabilities, quadrupole and magnetic moments with available experimental data. We have confirmed structure of high-spin states of these two nuclei which were tentatively assigned in the recent experimental work. In the case of $^{87}$Sr, for positive parity states up to $\sim$ 7.5 MeV, both interactions predict very good agreement with experimental data, while negative parity states are slightly suppressed in jj44b calculation.For the $^{87}$Zr nucleus, the jj44b interaction predicts higher energies for the negative parity states beyond $J \geq 27/2^{-}$. The configuration, which have one hole in $\nu g_{9/2}$ orbital, is responsible for generating the states in $^{87}$Sr. In the case of $^{87}$Zr, low-lying positive parity states come with the configuration having three holes in the $\nu g_{9/2}$, while the odd-parity states have configuration $\nu (f_{5/2}^{-1}g_{9/2}^{-2})$.