Chapter 49 - Solvation dynamics of coumarin 153 in benzene-acetonitrile and benzene-methanol mixtures: A Molecular Dynamics study

Abstract

Time-resolved fluorescence from sub-picosecond to the nanosecond time-scale of dye molecules, such as, coumarins has been widely used to study solvation dynamics in liquids. As the dye is photo-excited, its dipole moment abruptly changes. Then by monitoring the time-dependent fluorescence energy one can have access to the solvent dynamical response to the charge reorganization in the dye. The microscopic interpretation of these experiments has greatly benefited from Molecular Dynamics (MD) studies. Recently, few experimental and theoretical works have been performed on solvation dynamics in liquid mixtures. A number of new phenomena can arise in mixtures that are not present in pure solvents, like association, mutual diffusion, and preferential solvation. This chapter presents a Molecular Dynamics study of the time-dependent fluorescence of coumarin 153 (C153) in benzene-acetonitrile and benzene-methanol mixtures. The solvation dynamics in benzene-acetonitrile mixtures is analyzed by inspection of the time-dependent local populations of the two constituents around the coumarin dye.