A recoil-distance Doppler shift experiment has been performed using the ${}^{102}\mathrm{Pd}({}^{19}\mathrm{F},p2n$) reaction at a beam energy of 73 MeV to measure the lifetime of excited states in ${}^{118}\mathrm{Xe}$. The differential decay-curve method using $\gamma \gamma$ coincidences and a gating procedure that allows to extract the lifetime without feeding assumptions has been employed. The lifetimes obtained for the yrast states up to spin-parity $8^{+}$ are compared with interacting boson model calculations and ${}^{118}\mathrm{Xe}$ can be classified as a transitional nucleus between the spherical and a deformed shape. Systematics of the $B\left(E2\right)$ values for the $2^{+}\to 0^{+}$ and $4^{+}\to 2^{+}$ transitions in the isotopic chains of tin, tellurium and xenon are presented. It is proposed that a “critical point” exists at which the $B(E2;4^{+}\to 2^{+})/B(E2;2^{+}\to 0^{+})$ ratio drops to unity for lower neutron numbers within the isotopic chain. The position of the “critical point” varies with proton number, i.e., it is presumed to be located at the same mass number $A=114$ in the Sn, Te, and Xe isotopes.

• Received 27 May 2020
• Accepted 7 December 2020

DOI:https://doi.org/10.1103/PhysRevC.102.064318