Prediction of the Spin-Parities and the Magnetic Moments for the Ground States of Proton-rich Nuclei with Z = 21–30

The present paper reports on the spin-parities and the magnetic moments for the ground states of
44 proton-rich isotopes with Z = 21−30 and A = 36−57, which are important for studies of either
reaction rates in X-ray bursts or nuclear structure. These nuclear properties were calculated based
on the single-particle shell model. The spins of the concerned nuclei were compared to available
experimental data adopted from the NuDat database to evaluate the variations in the astrophysical
rates of the rp-process reactions. We found discrepancies, due to the deformed nuclear structure,
between the present results and those reported in the NuDat database. The spin uncertainties result
in large variations, 13% – 200%, in the astrophysical rates of the rp-process reactions. In particular,
the spin uncertainties of the 44V and the 46−49Mn isotopes significantly affect the astrophysical rates
of the reverse reactions of the proton captures 43Ti(p, γ)44V(p, γ)45Cr, 45Cr(p, γ)46Mn(p, γ)47Fe,
47Mn(p, γ)48Fe, 47Cr(p, γ)48Mn(p, γ)49Fe, and 48Cr(p, γ)49Mn(p, γ)50Fe. Moreover, the magnetic
moments of most of the isotopes were predicted for the first time. The results show that the
magnetic moments are in the order of μp(1f7/2) > μp(2p3/2) > μn(1d3/2) > μn(1f7/2) for the nuclei
having an unpaired nucleon in the proton/neutron shells. The present study suggests that reliable
calculations and/or measurements for the properties of proton-rich nuclei are highly demanded.