Photolysis of uranium hexafluoride and some reaction variables affecting the apparent quantum yield

Gas-phase thermal dissociation of uranium hexafluoride: Investigation by the technique of laser-powered homogeneous pyrolysis

“…An in-house reference spectrum for 8-UF5 displayed absorption features at -625, 570, and 430 cm", whereas Jacob (1973) reports the spectrum of B-UF5 to contain features at -605, 573, and 512 cm", with a broad band at 390 cm-'. It appears probable that the nonvolatile residue in our photolysis experiment was 8-UF5 condensation product, similar to that reported by Lewis et al (1979).…”

“…In the absence of trapping agent, the apparent quantum yield for the photolysis of UF6 at moderate gas densities is less than unity, due to UF5 + F recombination; however in the presence of H2, the apparent quantum yield is substantially above unity [Andreoni et al (1980), Lewis et al (1979)l. This indicates a net reduction of uF6 by H2 or fluorine abstraction from UF6 by atomic hydrogen.…”

“…Radiation was supplied by a 200-W xenon-mercury lamp, with filtering at the detector side of the reactor to wavelengths between 220 and 370 nm. Light with wavelengths <415 nm is energetic enough to photolytically decompose m6 to yield fragments identical to those produced by thermal decomposition [Lewis et al (1979)…”

“…The recombination reaction between UF5 and atomic fluorine [reverse reaction Eq. 3] is relatively rapid l. (Note that UF5 which does not recombine with atomic fluorine tends to polymerize and to condense out as solid B-UF5 near room temperature [Lewis (1979), l.…”

“…Estimated rate constants for some reactions of interest, including selected reactions of atomic fluorine, are given in Table 7. Molecular hydrogen reacts very rapidly with atomic fluorine (see Table 7 ) , and it has been used as a trapping agent for atomic fluorine produced by the W-photolysis of uF6 [see Lewis et al (1979), Andreoni et al (1980), Lyman et al…”