Rotational properties and blocking effects in N = 152 isotones 254No, 255Lr, and 256Rf

Abstract

Abstract The ground-state bands in the N = 152 isotones 254No, 255Lr, and 256Rf are investigated by using the cranked shell model (CSM) with pairing correlations treated by the particle-number-conserving (PNC) method. The experimentally kinematic moments of inertia are all reproduced quite well by the PNC-CSM calculations, and the contributions to J(1) from neutrons exhibit remarkable similarities. Compared to 254No, the observed identity of J(1) in 256Rf is due to the negligible contribution to J(1) from the two more protons partially occupying the π[514]7/2, π[521]1/2, and π[624]9/2 orbitals. The increase of J(1) observed in the odd-A nucleus 255Lr, compared to those of the neighboring even-even isotones 254No and 256Rf, is attributed to the contribution of proton j(1)([521]1/2) due to the blocking of nucleon on the proton π[521]1/2 orbital. Compared to the case in heavier isotones 255Lr and 256Rf, the different behavior of B(E2) value above hω ∼ 0.20 MeV in 254No is predicted due to the level π[514]7/2 crossing with π[521]1/2.