Local suppression of collectivity in the N=80 isotones at the Z=58 subshell closure
Phys. Rev. C
Background: Recent data on ๐=80 isotones have suggested that the proton ๐โก(1โข๐7/2) subshell closure at ๐=58 has an impact on the properties of low-lying collective states.
Purpose: Knowledge of the ๐ตโก(๐ธโข2;2+
1โ0+
1) value of 140Nd is needed in order to test this conjecture.
Method: The unstable, neutron-rich nucleus 140Nd was investigated via projectile Coulomb excitation at the REX-ISOLDE facility with the MINIBALL spectrometer.
Results: The ๐ตโก(๐ธโข2) value of 33(2) W.u. expands the ๐=80 systematics beyond the ๐=58 subshell closure.
Conclusions: The measurement demonstrates that the reduced collectivity of 138Ce is a local effect possibly due to the ๐=58 subshell closure and requests refined theoretical calculations. The latter predict a smoothly increasing trend.