Dirac phenomenological analyses of the proton inelastic scatterings from Ni isotopes*

Dirac analyses are performed for the proton inelastic scatterings from Ni isotopes using an optical potential model and the first order collective model. Dirac coupled channel equations are solved phenomenologically using the sequential iteration method by varying the optical potential and deformation parameters, using a computer program. It is found that relativistic calculations based on the Dirac equation can describe the experimental data for the intermediate energy proton inelastic scatterings from the Ni isotopes reasonably well, showing a little better agreement with the data than the nonrelativistic calculations based on the Schroedinger equation. The Dirac equations are reduced to the Schroedinger-like second-order differential equations and the obtained effective central and spin-orbit optical potentials are analyzed by considering mass number dependence. The deformation parameters for the low-lying excited states at the Ni isotopes obtained from the Dirac phenomenological calculations are found to agree well with those obtained from the nonrelativistic calculations.