Deterministic identifiability of two-state excited-state models with transients: Recovery of deactivation rate constants

A deterministic identifiability analysis of kinetic models of two-state excited-state processes in the presence of transient effects is performed to establish the conditions for the unique determination of the excited-state species deactivation rate constants with no assumption regarding the kinetics of interconversion in the excited state. It is necessary that decays of at least one excited-state species can be monitored separately to uniquely determine the excited-state species deactivation rate constants. This conclusion holds for reversible and irreversible intermolecular as well as intramolecular excited-state processes in the presence of transient effects. Sufficient conditions for the recovery of the deactivation rate constants are established for several cases of practical relevance. (C) 1999 American Institute of Physics. [S0021-9606(99)01203-9].