Fluorescence quenching of 2,2 ''-dimethyl-p-terphenyl by carbon tetrachloride in binary mixtures

Abstract

The fluorescence quenching of 2,2 ''-dimethyl-p-terphenyl (DMT) by carbon tetrachloride (CCl4) was investigated in different solvent mixtures of benzene and acetonitrile at room temperature (300 K). A positive deviation from linearity was observed in the Stern-Volmer plots for all the solvent mixtures. This could be explained satisfactorily by static and dynamic quenching models. The nonlinearities in the S-V plots are interpreted in terms of ground state complex model and the sphere of action static quenching model. The results suggest that positive deviations in the S-V plot are due to the presence of both static and dynamic quenching processes. To explain that bimolecular reactions are diffusion limited, we have used finite sink approximation model. Various rate parameters for the quenching process have been determined by static and dynamic quenching models. The dynamic quenching constant depends on the solvent polarity and indicates that quenching reaction is diffusion limited.