Lifetime and Quenching of Anthracene Fluorescence in the Vapor Phase

Abstract

The fluorescence lifetime and self‐quenching of anthracene vapor has been examined as a function of temperature. The fluorescence lifetime in the absence of quenching is found to be 5.7±0.2 nsec and is independent of temperature over the range 200° to 300°C. This value, together with published Stern—Volmer constants is used to determine the quenching probability for quenchers such as O₂ and NO. Probabilities considerably less than unity are obtained. The second‐order rate constant for self‐quenching of anthracene vapor is found to have a negative temperature coefficient. The previously reported negative coefficient found in the Stern—Volmer constant for self‐quenching can be explained by a temperature effect on the actual quenching process without resort to excimer decomposition. Vapor‐phase absorption and fluorescence spectra are reported. The oscillator strength and the quantum yield calculated from the actual and natural lifetimes are compared with corresponding values for solution.