Mean lifetimes of the low-lying positive-parity yrast states up to $J^{\pi }=6^{+}$ in ${}^{116}\mathrm{Te}$ were measured with the recoil distance Doppler shift method, and the corresponding $B$($E2$) values were deduced. Using our values for ${}^{116}\mathrm{Te}$ and the most recent measured transition strengths for the other isotopes in this region, we show that the $B$($E2$) values, especially those of the $2^{+}\to 0^{+}$ transition, show a smooth evolution of quadrupole collectivity, with only a slight asymmetric behavior across the middle of the shell, in contrast to the one found in Sn isotopes. The transition strengths of even-even Te isotopes are then compared with systematic theoretical calculations within the shell model using the realistic pairing plus multipole terms with monopole interaction and the large-scale shell-model configuration-interaction approach with a realistic interaction, while the projected shell model is applied to calculate only the structure of ${}^{116}\mathrm{Te}$. The latter model gives a very good description of the individual $B$($E2$) values in ${}^{116}\mathrm{Te}$, while the first two models predict a stronger asymmetric behavior across the middle of the shell than the one observed experimentally.

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• Collective levels
• Electromagnetic transitions
• Lifetimes & widths
• Nuclear structure & decays
• Shell model
• 90 ≤ A ≤ 149