Octupole vibrations in the even mercury and lead isotopes

Prominent groups are observed corresponding to excited states in the region of 2.6 MeV in the scattering of 24 and 27 MeV α-particles from ^{198, 200, 202, 204}Hg and ^{204, 206, 208}Pb. For each of the Pb isotopes the state concerned is identified with the known 3^? octupole vibration. Angular distribution measurements for scattering to the Pb and ²⁰⁴Hg states are in agreement with octupole-vibration coupled-channels predictions, and systematic trends suggest that the states observed in the isotopes ^{198, 200, 202}Hg can also be attributed to octupole vibrations.