Fluorescence decays and photon propagation times.

The effect of the time of flight of the exciting and emitted photons on fluorescence decays is studied. Experimental results for a long lifetime molecule (coronene) are analysed according to the fluorescence decay law previously obtained by the authors. The developed model accounts well for the main features of the observations. The inclusion of photon propagation times is essential for a correct description of the fluorescence decays under the described circumstances.