The lifetimes of the first excited $2^{+}$, $4^{+}$, and $6^{+}$ states in ${}^{98}\mathrm{Zr}$ were measured with the recoil-distance Doppler shift method in an experiment performed at GANIL. Excited states in ${}^{98}\mathrm{Zr}$ were populated using the fission reaction between a $6.2\mathrm{MeV}/\mathrm{u}$ ${}^{238}\mathrm{U}$ beam and a ${}^9\mathrm{Be}$ target. The $\gamma$ rays were detected with the EXOGAM array in correlation with the fission fragments identified by mass and atomic number in the VAMOS++ spectrometer. Our result shows a very small $B(E2;2_1^{+}\to 0_1^{+})$ value in ${}^{98}\mathrm{Zr}$, thereby confirming the very sudden onset of collectivity at $N=60$. The experimental results are compared to large-scale Monte Carlo shell model and beyond-mean-field calculations. The present results indicate the coexistence of two additional deformed shapes in this nucleus along with the spherical ground state.

Lifetimes of excited states in ${}^{211}\mathrm{At}$ were measured using the electronic $\gamma -\gamma$ fast timing technique. The nucleus of interest was populated in a ${}^{208}\mathrm{Pb}({}^6\mathrm{Li},3n){}^{211}\mathrm{At}$ fusion-evaporation reaction at the FN Tandem accelerator of the Institute for Nuclear Physics, University of Cologne. The lifetimes of the $17/2_1^{-}$ and $23/2_1^{-}$ states were determined, together with an upper limit for the $13/2_1^{-}$ state. The experimental results are compared to two shell-model calculations, one using a semiempirical interaction for three particles in a single $j=9/2$ shell and the other using the modified Kuo-Herling interaction in a multi-$j$ model space.

Lifetimes of low-spin excited states in ${}^{98}\mathrm{Zr}$ were measured using the recoil-distance Doppler-shift technique and the Doppler-shift attenuation method. The nucleus of interest was populated in a ${}^{96}\mathrm{Zr}({}^{18}\mathrm{O},{}^{16}\mathrm{O}){}^{98}\mathrm{Zr}$ two-neutron transfer reaction at the Cologne FN Tandem accelerator. Lifetimes of six low-spin excited states, of which four are unknown, were measured. The deduced $B\left(E2\right)$ values were compared with Monte Carlo shell model and interacting boson model with configuration mixing calculations. Both approaches reproduce well most of the data but leave challenging questions regarding the structure of some low-lying states.