Background: Recent data on $N=80$ isotones have suggested that the proton $\pi \left(1g_{7/2}\right)$ subshell closure at $Z=58$ has an impact on the properties of low-lying collective states.

Purpose: Knowledge of the $B(E2;2_1^{+}\to 0_1^{+})$ value of ${}^{140}$Nd is needed in order to test this conjecture.

Method: The unstable, neutron-rich nucleus ${}^{140}$Nd was investigated via projectile Coulomb excitation at the REX-ISOLDE facility with the MINIBALL spectrometer.

Results: The $B\left(E2\right)$ value of 33(2) W.u. expands the $N=80$ systematics beyond the $Z=58$ subshell closure.

Conclusions: The measurement demonstrates that the reduced collectivity of ${}^{138}$Ce is a local effect possibly due to the $Z=58$ subshell closure and requests refined theoretical calculations. The latter predict a smoothly increasing trend.

• Received 28 March 2013

DOI:https://doi.org/10.1103/PhysRevC.88.021302