$2\pi 1\nu$ states populated in ${}^{135}\mathrm{Te}$ from ${}^9\mathrm{Be}$-induced reactions with a ${}^{132}\mathrm{Sn}$ beam

$\gamma$-ray transitions in ${}^{134}\text{Te}$, ${}^{135}\text{Te}$, and ${}^{136}\text{Te}$ were measured from ${}^9\text{Be}$-induced reactions with a radioactive ${}^{132}\text{Sn}$ beam at a sub-Coulomb barrier energy of 3 MeV per nucleon using particle-$\gamma$ coincidence spectroscopy. The transitions were selected by gating on alpha-like particles in a CsI detector following a combination of $({}^9\text{Be},\alpha 1n)$, $({}^9\text{Be},\alpha 2n)$, and $({}^9\text{Be},\alpha 3n)$ incomplete fusion-evaporation reactions. Distorted-wave Born approximation calculations suggest little to no contribution from the $({}^9\text{Be},{}^7\text{He})$, $({}^9\text{Be},{}^6\text{He})$, and $({}^9\text{Be},{}^5\text{He})$ direct reactions.$\gamma$-ray transitions from previously known $2^{+}\otimes \nu 2f_{7/2}$ and $4^{+}\otimes \nu 2f_{7/2}$ multiplet members in ${}^{135}\text{Te}$ are observed. A new $\gamma$ ray is observed, assigned to the third-excited state in ${}^{135}\text{Te}$, and new $2^{+}\otimes \nu 2f_{7/2}$ multiplet members are suggested. In addition, spin assignments are made by using recent one-neutron transfer data. The updated experimental data for ${}^{135}\text{Te}$ are compared to shell-model calculations for a relatively complete set of states up to the yrast ${15/2}^{-},4^{+}\otimes \nu 2f_{7/2}$ multiplet member at 1505 keV.

Figure 1

$\gamma$-ray spectrum from single alpha-like particle gate. Transitions labeled in gray are contaminants from ${}^{132}\text{Sn}({}^9\text{Be},{}^8\text{Be}\to 2\alpha ){}^{133}\text{Sn}$.

Figure 2

Partial level diagram for ${}^{134,135,136}\text{Te}$. The dashed lines represent unobserved states and transitions.

Figure 3

Comparison between experimental and theoretical states in ${}^{134,135,136}\text{Te}$. For ${}^{135}\text{Te}$, the transitions are included if the strongest branch is not to the $7/2^{-}$ ground state.