Chemical quenching by water of the photoexcited uranyl ion in aqueous acidic solution

Several unusual features of uranyl photophysics in aqueous acidic solution, which we have previously explained by a more involved photophysical scheme than that generally adopted, are further clarified quantitatively. From concentration-quenching studies in H2O and D2O, it can be shown that the decrease in the luminescence yield on changing from D2O to H2O is due to a more active H-abstraction from H2O than of D from D2O by the highly reactive (5f, δu or ϕu), π3u luminescent state of uranyl.