Underlying Physics of Identical Odd-and Even-Mass Bands in Normally Deformed Rare-Earth Nuclei

The microscopic mechanism of the identical odd-and even-mass number nuclear bands in normally deformed rare-earth nuclei was investigated using the particle-number conserving (PNC) method for treating nuclear pairing correlation. It was found that the odd particle of an odd-A identical band always occupied a cranked low j and high Ω Nilsson orbital (e.g. proton 404]7/2, 402]5/2). On the contrary, if the odd particle occupies an intruder high j orbital (e.g. neutron 633]7/2, proton 514]9/2), the moment of inertia of the odd-A band was much larger than that of neighboring even-even ground state band. The observed variation of moment of inertia (below bandcrossing) was reproduced quite well by the PNC calculation, in which no free parameter was involved. The strengths of monopole and Y₂₀ quadrupole interactions were determined by the experimental odd even differences in binding energy and bandhead moment of inertia.