Nuclear-nucleus collisions: intrinsic motion with external correlations

Nucleus-nucleus collision, its intrinsic motion with external correlations are discussed. A consistent treatment of collective and intrinsic motion allows to include external correlations beyond the mean field approach. These correlations represent fluctuations of the external mean field. These fluctuations change the occupation numbers of the single-particle states and must be considered toge-- ther with the two-body collisions. Equilibration and relative motion are intimately connected because the collision term becomes operative, via the time-dependence of the external mean field