used to analyze the data. Briefly, the model postulates that inside a
critical volume around the fluorophore all quenchers will have unit
quenching probability. Under such assumption, the otherwise linear
Stern-Volmer plot will bend up at high quencher concentrations.
here F and F0 correspond to the fluorescence intensity for a given
quencher concentration [Q] and for [Q]=0, respectively, KSV is the
Stern-Volmer quenching constant, V is the excluded volume for the
quencher-fluorophore pair, τ0 is the fluorophore excited state lifetime
in absence of quencher and kq is the apparent microscopic bimolecular
quenching constant [26,27].