Molecular dynamics simulation of a model fluorescence quenching reaction A*+B→B (A* was fluorophore and B was quencher molecule) in a hard-sphere liquid where the fluorophore was excited for the first time or re-excited shortly after a bimolecular quenching process was carried out. The effects of light intensity upon the temporal behavior of the fluorescence quenching kinetics were obtained by a summed form of an appropriate convolution integral using the simulation data. The convoluted results were compared with a general theoretical framework for the quenching kinetics where the exciting light pulse had a short but finite duration. The theory was based on hierarchy of phenomenological kinetic equations involving reactant molecule distribution functions. The alone effect of potential of mean force was examined and the radiation boundary condition was considered. Improvements over the simplest version of the Smoluchowski theory were found. Considering the error introduced due to truncation of repeated excitation of A at the level of first repeated excitation (after a bimolecular process) the agreement between theory and simulation was excellent under certain limiting time profile of the exciting light pulse.

Light Intensity Effects on Diffusion-Influenced Fluorescence Quenching in a Hard-Sphere Liquid: Molecular Dynamics Simulation and the Many-Body Smoluchowski Equation Approach. Bandyopadhyay, T.: The Journal of Chemical Physics, 1995, 102[24], 9557-64