Determination of parameters of dynamic models in time-resolved spectroscopy

To obtain information on processes in a medium under study by the methods of pulsed spectroscopy, the optical response to a short-term external action is measured. If the processes in a medium are described by a linear set of usual differential equations, the signal shape represents a sum of several exponential components; in other cases, the signal is more complicated. The methods of separation of exponential components in a noisy signal have been developed rather well, but the parameters of the signal which are observed may often be connected only implicitly with the parameters of the dynamic model, which are of interest for an experimenter. In this paper we show how the methods of sensitivity analysis can be applied to estimate the parameters of a dynamic model from experimental relaxation signals. The possibilities of this technique are studied for model problems and for processing the experimental data obtained in studies of the kinetics of radiative and collisional processes in helium.