Levels ofTb155,157,159,161Excited in Helium - Induced Single-Proton-Transfer Reactions

Energy levels of ${}_{}{}^{155,157,159,161}{}_{}{}^{}\mathrm{Tb}$ have been studied through the (${}_{}{}^3{}_{}{}^{}\mathrm{He},d$) and ($\alpha ,t$) reactions on ${}_{}{}^{154,156,158,160}{}_{}{}^{}\mathrm{Gd}$, run with 25.5-MeV ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and 27.0-MeV $\alpha$ particles, respectively. Distortedwave Born-approximation analysis was used to interpret the reaction results, with transferred $l$ values obtained from the comparison of the experimental and theoretical values of the cross-section ratio, $R=\frac{d\sigma ({}_{}{}^3{}_{}{}^{}\mathrm{He},d)}{d\sigma (\alpha ,t)}$. The spectroscopic information obtained was compared to the theoretical predictions of the Nilsson model. Corrective terms added included the Coriolis and pairing interactions. Many of the levels excited were identified as members of rotational bands built on Nilsson single-particle configurations. Identified in all four nuclei are the [411↑], [413↓], [532↑], [404↓], [402↑], and [411↓] Nilsson configurations. Other bands identified are the [541↓] in ${}_{}{}^{157,159,161}{}_{}{}^{}\mathrm{Tb}$, the [523↑] in ${}_{}{}^{159,161}{}_{}{}^{}\mathrm{Tb}$, the [411↑] $\gamma$ mixed configuration in ${}_{}{}^{155,157,159}{}_{}{}^{}\mathrm{Tb}$, and the [514↑] configuration in ${}_{}{}^{155}{}_{}{}^{}\mathrm{Tb}$.