Inelastic electron scattering fromPb208at 180°

Inelastic cross sections for 180° electron scattering from ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ have been measured at incident energies of 40.5, 50.4, 60.3, and 75.2 MeV. Transverse electric form factors have been determined for the $3^{-}$ state at 2.614 MeV, the $5^{-}$ states at 3.198 and 3.708 MeV, the $2^{+}$ states at 4.085 and 6.21 MeV, the $4^{+}$ state at 4.323 MeV, and the $6^{+}$ state at 4.422 MeV. The results for these natural parity states are compared to the predictions of an incompressible, irrotational current model, and of a particle-hole model. All transverse electric form factors show strong contributions from intrinsic magnetization currents. Transverse form factors were obtained for the proposed $1^{+}$ state at 4.84 MeV, for the group of $1^{+}$ states at 7.48 MeV, and for several proposed $2^{-}$ states. A search for $M1\mathrm{}$ transition strength was made up to excitation energies of 19 MeV. The future of electron scattering as a tool for probing $M1\mathrm{}$ strength in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ is discussed.