Models for gas-phase coherent kinetics including correlations with flow quantities

A general framework is established for describing the transport of atomic particles with internal levels under such conditions that phase relationships in the quantum internal states are relevant and such relationships are correlated to the translational state. A transport equation is derived, based on appropriate definitions of the convective derivative and the collision term. The physical basis of the method is discussed at some length to grant consistency with quantum mechanical principles. A numerical example is provided, showing the revival of Rabi oscillations associated to the decay of correlations between translational and internal state in a model test case. (C) 2001 Elsevier Science B.V. All rights reserved.