Spectra, lifetimes and energy transfer for uranyl species in solution

Abstract

The lifetimes for various uranyl species formed under varying conditions of solvents, pH, etc., have been measured. A large variation in lifetimes from about 10 µs for hydrolytic UO²⁺2 (UO₂)_n species to about 900 µs for anion complexed UO₂(NO₃)₂ species is observed. The lifetime data are shown to be in agreement with the calculated values when care is taken to isolate the contribution to absorption due to the F series only. The samples in which more than one species are present in emission, show energy transfer from the higher energy species to the one having lower energy of excitation. As a result of this the lifetime of the donor is decreased and that of the acceptor is increased. The donor decay is found to be exponential. A rise time is also observed in acceptor emission. The energy transfer mechanism is found to be of the Stern-Volmer type transfer.