RESONANTLY ENHANCED EXTERNAL HEAVY-ATOM EFFECT IN ORGANIC GLASSES

A model of a mixed solution in an organic glass is considered where the lowest triplet state of one of the solutes borrows intensity from a triplet state of another solute, while overlapping site energy distributions of the two solutes allow the pertinent triplet states to be degenerate for some borrower and lender molecules. It is demonstrated that intensity borrowing is greatly enhanced in that case. The shape of the borrower phosphorescence excitation spectrum is discussed, as well as some other consequences of the model. The model is applied for the interpretation of the properties of the 1-iodonaphthalene/perfluoronaphthalene solution in a glassy matrix, and allows one to rationalize some features that have not been understood before. © 1990.