Abstract
The S 2→S 0 and S 2→S 1fluorescence spectra of azulene have been studied in a low temperature glass using laser excitation into the S 2 state. The former emission shows a sharp zero‐phonon line pattern, a feature which is characteristic of energy selection experiments. The latter emission consists of broad Gauss‐shaped vibronic bands which show the full inhomogeneous matrix width. Solute–solvent interactions which depend strongly on the nature of the excited electronic state restrict the energy selection effect to the resonant electronic transition.