Figure 4.

Schematic illustration of an user-defined (tutorial) model. In this model, the states X and Y are initially populated and the decay independently and irreversibly with the decay rate k₀ and k₁, respectively, finally populating state Z. This state irreversibly decays back to the ground state with the rate-constants k₂. The corresponding rate equations for the concentrations of X, Y, and Z are displayed.