A description of the dynamics and thermodynamics of vibration damping in axially deformed nuclei

The Quantal Brownian Motion (QBM) model of nuclear vibration damping is adapted to describe an axially deformed nucleus where a giant oscillatory mode becomes excited. Several simplifying assumptions are imposed in order to obtain an operative version of the QBM model. Within the restrictions posed by this set of hypotheses, it is found that a system resembling the nuclide 166Er, as an illustration, undergoes both dynamical and thermodynamical behavior in a consistent scheme of magnitudes. The value of energies, temperatures and entropies at equilibrium fit a closed thermodynamical model concerning oscillators coupled to fermionic reservoirs. In the present approach, it is seen that the nucleonic excitations that provide the doorways to mode decay can be clearly split into two sets, or separate heat baths, for the components of the axially symmetric vibration. (orig.)