PARTICLE-NUMBER CONSERVING TREATMENT FOR THE GROUND STATE BANDS IN EVEN-EVEN TRANSFERMIUM NUCLEI

The ground state bands observed in even-even transfermium nuclei Fm-250 and No-252,No-254 are investigated by the cranked shell model with the particle-number conserving treatment for the monopole and quadrupole pairing correlations. The experimental variations of the kinematic moment of inertia with rotational frequency are reproduced very well in our calculation. Our results show bankbendings of (sic)((1)) at (h) over bar omega approximate to 0.275 and 0.300 MeV in No-252 and No-254, respectively. The detailed information about the contribution to alignment from each cranked single particle level exhibits that the backbending is mainly due to the rapidly aligned angular momentum of proton 1j(15/2) [770]1/2 pairs and neutron 2h(11/2) [761]3/2, 1j(15/2) [734]9/2 pairs the band crossing.