Excited-State Perylene—Pyrene Interactions: Relation to the Interpretation of Excimer Emission

Publisher Website
Google Scholar
Abstract
The ``anomalous'' emission properties of perylene—pyrene mixed crystals have been re-examined. The results of this study demonstrate that the unusual character of the mixed-crystal emission spectra is primarily due to reabsorption of ``normal'' monomeric perylene emission, rather than to a very large excited-state perylene—pyrene interaction as previously suggested. Studies of the emission and absorption properties of perylene in liquid solutions containing pyrene indicate, however, that there is a significant excited-state perylene—pyrene interaction. This excited-state interaction shifts the perylene emission over 150 Å to the red, reduces the intensity, and produces a loss of some of the vibronic structure of the perylene emission. Because the lowest excited singlet states of perylene and pyrene are far from degenerate in energy, the excited-state perylene—pyrene interaction cannot be due to a resonance interaction. Preliminary experimental results suggest that the excited-state interaction is of charge-transfer character.

This publication has 20 references indexed in Scilit: