Rotational bands studies of the 169Er nucleus

The properties of low-lying levels in 169Er have been studied within the Quasiparticle-Phonon coupling plus Rotor Model (QPRM). The correlation of the quasiparticle in the intrinsic field is described through the BCS approximation and the individual excitation is required in a deformed Nilsson field. The Coriolis term in the model Hamiltonian has been treated, in many cases, being found to produce a strong coupling between the intrinsic and rotational motion. This model treats all the nucleons equivalently as particles moving in a rotating mean field and makes no distinction between core and valence particles with the odd-A nucleus that is treated as a system of quasiparticle coupled to an even-even core. We show that the effect of the positive parity i13/2 decoupled band can be reproduced. The theoretical level schemes of 169Er is established and compared to the existing experimental data.