Deactivation and luminescence lifetimes of excited uranyl ion and its fluoro complexes

The luminescence decay of uranyl fluoride complexes has been studied in broad fluoride concentration range. Biexponential decay were found with a shorter lifetime component varying between 1.7 and 19.1 μs, while a longer component is in the range from 49 to 156 μs. The fluoride saturated solution exhibits single exponential decay with a lifetime of 207 μs. The activation parameters for the decay of [UO2F]+ complex have been determined. The results have been compared to other studies and interpreted in terms of ligand exchange, which is proposed as a new deactivation pathway for excited uranyl fluoro complexes. (orig.)