Importance of the neutron-proton interaction for Zr isotopes

Abstract
Shell-model calculations are presented for 100,102,104Zr for most J values of interest. The theoretical energy spectra for 100,102Zr are in good agreement with the experimental values. The neutron 1g7/2 and the proton 1g9/2 orbits appear to have a strong correlation in their occupation numbers for all the states.