Influence of high-j intruder orbitals in odd mass transfermium nuclei 253No and 251Md

Rotational bands of 253No and 251Md are studied by the cranked shell model with particle-number conserving treatment for monopole and quadrupole pairing correlations. Observed bands are reproduced very well by theoretical results. A backbending of kinematic moment of inertia ℑ(1) is predicted at ℏω≈0.275MeV in bands of 253No. This is attributed to the simultaneous alignment of neutron 2h11/2(1/2[761]) and proton 1j15/2(1/2[770]) pairs. Only one signature band was observed in 251Md. We predict its signature partner band with a sharp backbending at very low frequency of ℏω≈0.15MeV. Backbendings of ℑ(1) in 251Md are the consequence of crossing between the proton 1/2[521] and 1/2[770] configurations. The sudden rise of ℑ(1) is mainly due to the large alignment of proton 1/2[770] pair.