Reactions of Laser-Ablated U Atoms with HF: Infrared Spectra and Quantum Chemical Calculations of HUF, UH, and UF in Noble Gas Solids

Reactions of laser-ablated U atoms with HF produce HUF as the major product and UH and UF as minor products, which are identified from their argon and neon matrix infrared spectra. Our assignment of HUF is confirmed by the observation of DUF and close agreement with observed and calculated vibrational frequencies and deuterium shifts in the vibrational frequencies. Our previous observation of the UH diatomic molecule from argon matrix experiments with H₂, HD, and D₂ as reagents is confirmed through its present observation with HF and DF, and with recent higher level quantum chemical calculations. The HF reaction provides a lower concentration of F in the system and thus simplifies the fluorine chemistry relative to similar U atom reactions with F₂, and the new matrix identification of UF here is consistent with recent high level calculations on UF. In addition, we find evidence for the higher oxidation state secondary reaction products UHF₂, UHF₃, and UH₂F₂.