Effect of solvent on the fluorescence quenching of organic liquid scintillators by aniline and carbon tetrachloride

The fluorescence quenching of MPNO1 and MPNO2 by aniline and 2-phenylindole by CCl4 has been carried out in different solvent mixtures of dioxan and acetonitrile at room temperature. The quenching is found to be appreciable and a positive deviation from linearity was observed in the Stern-Volmer plot in all the solvent mixtures. Various rate constants for the quenching processes have been determined using a modified Stern-Volmer equation. From the positive deviations of linear Stern-Volmer plots and the dependence of rate constants on the polarity of the solvents, it has been concluded that both static and dynamic quenching processes are responsible for the observed positive deviation in the Stern-Volmer plot.