States ofRb86: TheRb87(d,t)Rb86Reaction

The states of ${}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ were studied using the ${}_{}{}^{87}{}_{}{}^{}\mathrm{Rb}\mathrm{}(d,t)\mathrm{}{}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ reaction at 17.5-MeV incident energy. Spectra were obtained using an Enge split-pole magnetic spectrograph; over-all energy resolution was 9 keV. Angular distributions were obtained from 9 to 60° laboratory angle for 25 levels up to 2 MeV excitation. Comparison with distorted-wave Born-approximation calculations yielded unique $l$-value assignments for 18 transitions; absolute spectroscopic factors were also extracted. Implications about the structure of the low-lying states are pointed out. The significant excitation of the $J^{\pi }=2^{-}$ ground state of ${}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ indicates weak $3s_{\frac{1}{2}}$ and $2d_{\frac{5}{2}}$ admixtures in the ${}_{}{}^{87}{}_{}{}^{}\mathrm{Rb}$ ground state.