Terbium fluorescence quenching

The radial dependence of the fluorescence-quenching interaction between terbium, holmium, and neodymium in aqueous chloride solution was examined by Holloway and Kestigian (108a). From the concentration dependencies of the fluorescence lifetimes, they concluded that the probability for quenching interaction falls off as 1/r6, where r is the average spacing between the ions. If the mechanism of resonance transfer is assumed, the observed radial dependence implies a dipole-dipole interaction. 

He gives a fluorescent lifetime of about 700 jxscc for the terbium 5D4 state at 77°K. The fluorescence is quenched at room temperature. Unfortunately, the temperature dependence of the fluorescent lifetime was not measured. 

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