By fitting time-resolved measurements to models of diffusion influenced reactions it is possible to determine only parameters with no spatial dependence. The original set of distance-dependent parameters is reduced to a set of distance-independent parameters, and only these can be determined by fitting the model to the data. The present work demonstrates this point for reversible geminate recombination in one and three dimensions, showing how the reduced set of parameters is found by utilizing dimensional analysis or known analytic solutions. It is applied to the kinetic detection of proton-wires in the green fluorescent protein. (c) 2005 Elsevier B.V. All rights reserved.