Deviation of Nuclear Radii from a Smooth A Dependence for Neutron Data

Experimental values for r.m.s. charge density radii show deviations from a simple A dependence of several percent for statically deformed nuclei and around shell closures. These data, for both stable nuclei and nuclei away from the valley of stability, are well described by Hartree-Fock-Bogolyubov calculations carried out at Bruyères-le-Châtel. By using the neutron and proton r.m.s. radii from these same HFB calculations in conjunction with a folding model to produce an optical potential, we can then predict the expected results from neutron scattering experiments. We have made a detailed study of this procedure in the A=40–70 mass range. The calculated 14-MeV neutron nonelastic and total cross sections shows deviations of several percent from a smooth dependence on A. We conclude that using mean field – folding model calculations is useful for estimating neutron cross sections on nuclei both on and away from the valley of stability.