Pion scattering to collective excitations in /sup 90/Zr and /sup 118/Sn

Inelastic scattering of 163 MeV π- and π+ to the collective states of /sup 90/Zr and /sup 118/Sn was used to determine the neutron-proton composition of the transitions. The lowest 2+ and 3- states were examined for both targets, as were the low-energy octupole, giant quadrupole, and giant monopole excitations. Only slight deviations from the features expected for a hydrodynamic model are observed for the low-lying 3- and 2+ states of /sup 118/Sn, but these states are observed to be proton-like in /sup 90/Zr. The giant quadrupole resonances and giant monopole resonances in both targets show a significantly greater π- than π+ strength, while the low-energy octupole resonance is excited symmetrically