Gamma-ray cascades from nanosecond isomers in neutron-rich nuclei ${}^{67}\mathrm{Cu}$ and ${}^{64}\mathrm{Co}$ have been observed through heavy-ion deep-inelastic collisions of ${}^{198}\mathrm{Pt}{+}^{76}\mathrm{Ge}$ (8 MeV/nucleon) using an isomer-scope. In ${}^{67}\mathrm{Cu},$ an isomeric state at 3464 keV and its decay scheme have been established. The isomeric transition is a hindered $M1\mathrm{}$ transition between the ${15/2}^{+}$ and the ${13/2}^{+}$ states with main components of $(\pi p_{3/2}\nu g_{9/2}\nu f_{5/2}^{-1}{)}_{{15/2}^{+}}$ and $(\pi p_{3/2}\nu g_{9/2}\nu p_{1/2}{)}_{{13/2}^{+}},$ respectively. A fast $E3\mathrm{}$ transition between the $\pi g_{9/2}$ and the $\pi p_{3/2}$ single-particle states indicates strong particle-octupole vibration coupling in ${}^{67}\mathrm{Cu}.$ An isomeric state at 834 keV with $T_{1/2}=6.4\mathrm{}\left(3\right)\mathrm{}\mathrm{ns}$ has been identified in ${}^{64}\mathrm{Co}.$ Proton-neutron configurations of the levels established in ${}^{64}\mathrm{Co}$ are discussed.

• Received 27 June 2000

DOI:https://doi.org/10.1103/PhysRevC.62.054313