Monitoring the Reaction Dynamics of UF₆ by Cryogenic Layering and FTIR Spectroscopy

Uranium hexafluoride (UF₆) is a commonly used material feedstock for uranium enrichment processes. When introduced to water in the atmosphere, it reacts rapidly to form uranyl fluoride (UO₂F₂). Here, we investigate the UF₆ hydrolysis reaction by cryogenically trapping reaction intermediates and characterizing the trapped species by Fourier transform infrared (FTIR) spectroscopy. The reactant species are sequentially layered onto a diamond substrate held at 10K by a closed-cycle liquid helium cryostat. At this temperature, the hydrolysis reaction is not spontaneous and can be catalyzed by the introduction of heat. Upon heating, the reaction moves through several intermediate compounds before proceeding to the final UO₂F₂ product. Several previously unobserved bands appear while the reaction progresses. These bands may help to elucidate the mechanism behind UF₆ hydrolysis.