Transfer of electronic excitation energy between dye molecules in the channels of zeolite L

We show that the intercalation of dye molecules, which penetrate the cylinders from the bottom and the top surface, into the linear channels of zeolite L can be observed with the help of a fluorescence microscope. By means of a polarizer, we have proved the alignment of the dye molecules in the channels, because maximum luminescence appears parallel to the longitudinal axis of the microcrystals and extinction perpendicular to it. A simple and elegant experiment for the visual proof of the energy transfer from pyronine to oxonine in zeolite is based on the observation that both dyes are intercalated from an aqueous solution within about the same time. This leads to high dye concentrations in the zeolite and therefore to short distances between the molecules, which enables energy transfer between them. This experiment also allows a simple determination of the shortest distances between neighboring dye molecules along linear channels.