  The question of decoupling and freeze-out is reinvestigated and analysed in
terms of transparent semi-classical decoupling formulae, which provide a smooth
decoupling in time both, for single and two particle inclusive spectra. They
generalise frequently employed instantaneous freeze-out procedures and provide
simple relations between the damping width and the duration of the decoupling
process. The implications on physical phenomena arising from the expansion and
decay dynamics of the highly compressed hadronic matter generated in high
energy nuclear collisions are discussed.
