Time resolved electronic spectroscopy. I. Bimolecular rates for excimer formation

Abstract

The time delay in the build-up of excimer fluorescence for solutions of pyrene affords a means of testing the assumption that bimolecular quenching of fluorescence is diffusion-controlled. It appears that in solvents of low viscosity this is no longer the case. An apparatus is described with which measurements of fluorescence intensity at nanosecond intervals can be made using a simple versatile high- intensity lamp of short flash duration.