A comparison between a kinetics model and the familiar picture of femtosecond dynamics for direct bond breakage is presented. The kinetics model involves a series of consecutive first-order reactions between transient configurations of the molecule as the bond stretches, before it breaks, We show that in the limit where a large enough number of transient configurations are included, the kinetics model reproduces the molecular response expected from the dynamical picture in a classical, one-trajectory sense. (C) 2002 Elsevier Science B.V. All rights reserved.