It was possible to obtain reasonable results for our system with variation in parameters, but no fit is possible if parameters were fixed across decays, probably due to the fact that there were no uniform distribution in sample volume. In resonance energy transfer description model [Equation ], coefficient b describes concentration and availability of donor species, whereas β should be fixed to discrete values depending on the assumption of RET process properties, such as β = 2 in case of FRET β = 6, 3, 0.5 for systems with three-two-or one dimensional transfer process happening.