Simultaneous presence of static and dynamic component in the fluorescence quenching of Bis-MSB by CCl4 and aniline

The fluorescence quenching of 1, 4-bis2-(2-methylphenyl)ethenyl]-benzene (Bis-MSB) in toluene has been studied with carbon tetrachloride (CCl₄) and aniline by steady-state and transient methods. A positive deviation was observed in the Stern-Volmer (S-V) plot for both the quenchers. This indicates the presence of either static or transient quenching component in the overall dynamic quenching. The experimental data are analysed by sphere of action static quenching model. The value of radius of sphere of action determined from this model is greater than the sum of the radii of the Bis-MSB and respective quenchers. From the studies of temperature dependence of rate parameters and lifetime measurements, it could be explained that the positive deviation is due to the presence of a small static quenching component in the overall dynamic quenching. This fact suggests the simultaneous presence of static and dynamic component in the fluorescence quenching Bis-MSB by CCl₄ and aniline.