Analyzing power measurements for ²⁰⁹Bi(n,n) at 6 and 9 MeV and consistent dispersive optical-model analyses for n+²⁰⁹Bi and n+²⁰⁸Pb from -20 to +80 MeV

High-accuracy measurements of A_y(θ) data for elastic scattering for n+²⁰⁹Bi have been performed at 6 and 9 MeV. The data are incorporated into a large database of σ(θ), A_y(θ), and σ_T for n+²⁰⁹Bi covering the energy range 1.0-80 MeV. A complementary database is constructed for n+²⁰⁸Pb and a dispersive optical-model analysis is performed for both scattering systems while constraining many of the parameters to be identical for both systems. A good representation of both databases is obtained with conventional geometry and spin-orbit parameters. The ²⁰⁸Pb model predicts quite well the measured energies of valence single-particle and single-hole bound states. Occupation probabilities and spectroscopic factors for the same bound states are also calculated. Finally, a fully constrained model is presented in which the only differences between the n+²⁰⁸Pb and the n+²⁰⁹Bi systems are the Fermi energy and the isospin dependence in the real volume potential.