Nonadiabatic quasiparticle approach for rotation-particle coupling in triaxial odd-Anuclei

Abstract

We discuss the formulation of a nonadiabatic approach to study the rotational states in triaxially deformed odd-$A$ nuclei. The rotation-particle coupling is treated microscopically by coupling the triaxial rotor states of the even-even core with the states of the valence particle in order to obtain the matrix elements of the odd-$A$ system. We arrive at a nonadiabatic quasiparticle approach where the rotational states can have contributions from various quasiparticle states near the Fermi level. We bring out the advantages of this approach over the conventional particle rotor model with a fixed or variable moment of inertia. One clear evidence favoring our approach is the rotation alignment phenomenon which is demonstrated in the case of $^{137}\mathrm{Pm}$. We discuss our results for $^{136}\mathrm{Nd}$ and $^{137}\mathrm{Pm}$, and justify that this approach is suitable also for studying nuclei away from stability.