Back-angle elastic and inelastic scattering ofαparticles from the even Ni isotopes

Angular distributions for the elastic and inelastic scattering of $\alpha$ particles from the even Ni isotopes from 12.5 to 177.5° in the energy range from 18-27 MeV are reported. The ${\beta }_2$ coupling strengths to the first excited $2^{+}$ state in each isotope are extracted from the data and are compared to similar results obtained at higher energy. The lack of any backward enhancement in the cross sections, in contrast to results reported for lighter nuclei, is explained on the basis of the level densities in the compound system.