Dispersive coupled-channels optical-model potential with soft-rotator couplings for Cr, Fe, and Ni isotopes

Abstract

An approximate Lane-consistent dispersive coupled-channels optical potential is derived that describes nucleon-induced reactions on even iron isotopes. Realistic saturated couplings for ${}^{54,56,58}$Fe nuclei are built using nuclear wave functions of the soft-rotator model with the Hamiltonian parameters adjusted to reproduce the energy of the low-lying collective levels of these isotopes. $E2$- and $E3$-transition probabilities between low-lying collective levels are well reproduced. The comprehensive experimental database used in the fitting process includes all scattering data for neutron and proton scattering up to 200 MeV on iron nuclei. The derived potential is shown to be applicable to Ni and Cr isotopes, assuming the applicability of the soft-rotator model to these nuclei and to the odd ${}^{57}$Fe nucleus within the rigid-rotor model. The approximate Lane consistency of the derived potential is validated by describing the quasielastic $(p,n)$ scattering with excitation of isobaric analog states. Elastic and inelastic analyzing powers for both neutron- and proton-induced reactions are shown to be in good agreement with experimental data, demonstrating the reliability of the derived dispersive spin-orbit potential.