Effects of Rotation,Blocking and Octupole Deformation on Pairing Correlations in the U and Pu Isotopes
By including octupole correlations in the Nilsson potential,the ground-state rotational bands in the reflec-tion-asymmetric(RA)nuclei are investigated by using the cranked shell model(CSM)with the monopole and quad-rupole pairing correlations treated by a particle-number-conserving(PNC)method.The experimental kinematic mo-ments of inertia(MoIs)for alternating-parity bands in the even-even nuclei 236,238U and 238,240Pu,as well as parity-doublet bands in the odd-A nuclei 237U and 239Pu are reproduced well by the PNC-CSM calculations.The higher J(1)for the intrinsic s=-i bands in 237U and 239Pu,compared with the s=+l bands in the neighboring even-even nuclei 236,238U and 238,240Pu,can be attributed to the pairing gap reduction due to the Pauli blocking effect.The gradual increase of J(1)versus rotational frequency can be explained by the pairing gap reduction due to the rotation.The MoIs of reflection-asymmetric nuclei are higher than those of reflection-symmetric(RS)nuclei at low rotational frequency.Moreover,the inclusion of a larger octupole deformation ε3 in the RA nuclei results in more significant pairing gap reduction compared with the RS nuclei.
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