Core excitations up to $E_x=4\mathrm{}$ MeV in ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$ have been studied by the reactions ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}(p,p^{\prime }){}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$ and ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}\mathrm{}(p,t)\mathrm{}{}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$ at 40 MeV proton energy. The transferred angular momentum $L$ has been determined for each transition on the basis of the angular distribution shape. A quarter-plus-doublet pattern is consistently observed for the groups of states corresponding to the $2_1^{+}$, $3_1^{-}$, and $4_1^{+}$ states of the core nucleus ${}_{}{}^{62}{}_{}{}^{}\mathrm{Ni}$. This implies the existence of doublets arising from the coupling of collective states of the core with the $2p_{\frac{1}{2}}$ proton orbital, in addition to the quartets from the coupling with the $2p_{\frac{3}{2}}$ proton orbital considered in the conventional weak-coupling excited-core model. It is pointed out that the existence of a weak-coupling situation cannot be proved only on the basis of transfer-reaction data, and in this regard the importance of a comparative study of the inelastic-scattering and transfer-reaction data is emphasized.

NUCLEAR REACTIONS ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}\mathrm{}(p,t)\mathrm{}{}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$ and ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}(p,p^{\prime }){}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$, $E=40\mathrm{}$ MeV; measured $E_x$ and $\sigma \left(\theta \right)$, determined $L$. Resolution 16 keV for the ($p,t$), 20 keV for the ($p,p^{\prime }$). Enriched targets. Deduced excited-core multiplets.

• Received 30 December 1980

DOI:https://doi.org/10.1103/PhysRevC.23.1960