M. Sikorski et al., ON THE CONDITIONS NEEDED TO VERIFY A NONSTATIONARY DIFFUSION-MODEL BYKINETIC-ANALYSIS OF FAST FLUORESCENCE QUENCHING, Journal of luminescence, 69(4), 1996, pp. 217-227
Numerical experiments were carried out to test the feasibility of dist
inguishing florescence quenching kinetics based on the treatment of Sm
oluchowski, Collins and Kimball (SCK) from those showing single-expone
ntial decays (Stern-Volmer kinetics) for a series of emission lifetime
s lower than 1 ns corresponding to the measured lifetimes for seven th
ioketones in perfluoro-1,3-dimethylcyclohexane as solvent. Experimenta
l apparatus functions have been used to simulate the decays. The resul
ts show that it is possible to determine the parameters of the SCK dec
ay curve using appropriate equipment with short excitation sources and
a detector with adequate time resolution and using the nonlinear leas
t-squares fitting technique, provided the emission lifetime tau is lon
ger than the duration of the nonstationary diffusion phase. Correlatio
n coefficients are determined between the SCK function parameters, whi
ch explain the difficulties often encountered in fitting decay curves
to SCK theory. Parameter uncertainties have been estimated from a seri
es of simulations which experimentalists can use to ensure the paramet
ers, which they obtain from fitting fluorescence decay curves in the p
resence quenchers, are valid and not interdependent.