Laser-induced fluorescence of uranyl complexes in aqueous solutions: the role of diffusion-controlled excited states annihilation

Abstract

We present the analysis of diffusion-controlled annihilation of excited U(VI) complexes in aqueous media that leads to appearance of rapid non-exponential fluorescence decay. We show that under typical experimental conditions the impact of annihilation processes can't be neglected when determining U(VI) complexes fluorescence lifetimes: at excitation intensities between 10(6) W/cm(2) and 10(8) W/cm(2), the rate of excited states deactivation increases, and then an opposite trend is observed. The latter can be interpreted as the consequence of optical breakdown in water.