Dynamical aspects of thermal nuclear properties

We study the collective motion of a certain shape degree of freedom Q, close to local thermal equilibrium parametrized by the thermal entropy S. The extent to which S may be substituted by the more convenient choice of temperature T is discussed. The dynamics in Q and S are treated consistently within a locally harmonic approximation. The collective frequencies are determined by a secular equation, the structure of which is well known in nuclear physics. The effective coupling constant k, however, depends sensibly on thermal, quasi-static properties of the system. Its form differs from the one of previous approaches where dT/dt had been assumed zero. This difference, as well as the dependence of k on T (or S), is numerically estimated. Consequences for the dynamics in Q are demonstrated. Finally, for the case of strict harmonic motion, we compare our results to the one obtained if the concept of "diabetic" motion were plainly combined with that of equilibrium.