Evolution of quadrupole collectivity in N=80 isotones toward the Z=64 subshell gap: The B(E2; 2(1)(+) -> 0(1)(+)) value of Sm-142

It was shown that the evolution of the B(E2; 2(1)(+) -> 0(1)(+)) values in N = 80 isotones from Te to Nd is affected by the underlying subshell structure. This manifests itself in the observation of the local suppression of the B(E2) value at Z = 58 with respect to the neighboring nuclei Ba-136 and Nd-140. To investigate this shell sensitivity toward the Z = 64 subshell gap, the B(E2; 2(1)(+) -> 0(1)(+))) value of the unstable nucleus Sm-142 was measured utilizing the projectile Coulomb excitation technique. The radioactive ion beam (RIB) experiment was performed at the REX-ISOLDE facility at CERN. The B(E2) value of 32 (4) W.u. reflects the impact of the pi(1g(7/2) 2d(5/2)) subshell closure at Z = 64 with respect to a linear scaling of collectivity with valence proton number.