Nanosecond Time-Resolved Fluorescence Spectroscopy in the Physical Chemistry Laboratory: Formation of the Pyrene Excimer in Solution

The fluorescence lifetime and spectrum of pyrene in fluid solution depend on experimental conditions, including sample concentration, solvent viscosity, and the presence of dissolved oxygen. Students are introduced to nanosecond-domain transient spectroscopy in fluid solution by using a pulsed-laser apparatus to make direct measurements of the effects of these variables. They become familiar with the operation of a nitrogen laser and an associated apparatus for fluorescence spectra and lifetime measurements, including the optical and electronic hardware and the computer software used to acquire and analyze the data. The experiment specifically illustrates the role of sample concentration and solvent viscosity on fluorescence lifetimes and spectra, and the effects of argon purging to remove dissolved oxygen.