Bibliographic Citation
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Title | Reaction of fluorine atoms with monomeric and polymeric uranium pentafluoride |
Creator/Author | Lyman, J.L. ; Holland, R. |
Publication Date | 1987 Aug 27 |
OSTI Identifier | OSTI ID: 5916043 |
Other Number(s) | CODEN: JPCHA |
Resource Type | Journal Article |
Resource Relation | J. Phys. Chem. ; Vol/Issue: 91:18 |
Research Org | Los Alamos National Lab., NM |
Subject | 400702 -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials ;400500 -- Photochemistry; FLUORINE-- CHEMICAL REACTIONS;FLUORINE-- PHOTOLYSIS;URANIUM PENTAFLUORIDE-- CHEMICAL PREPARATION;URANIUM PENTAFLUORIDE-- CHEMICAL REACTIONS;URANIUM PENTAFLUORIDE-- PHOTOLYSIS; CHEMICAL REACTION KINETICS;EXPERIMENTAL DATA;LASERS;MEDIUM TEMPERATURE;MONOMERS;POLYMERS;QUANTITY RATIO;TIME DEPENDENCE |
Related Subject | ACTINIDE COMPOUNDS;CHEMICAL REACTIONS;DATA;DECOMPOSITION;ELEMENTS;FLUORIDES;FLUORINE COMPOUNDS;HALIDES;HALOGEN COMPOUNDS;HALOGENS;INFORMATION;KINETICS;NONMETALS;NUMERICAL DATA;PHOTOCHEMICAL REACTIONS;REACTION KINETICS;SYNTHESIS;URANIUM COMPOUNDS;URANIUM FLUORIDES |
Description/Abstract | The authors have measured the room-temperature rate constants for formation of UF/sup 6/ from the reaction of fluorine atoms with UF/sub 5/.^The rapid growth of UF/sub 5/ clusters (polymers) from the nascent monomeric species complicates the rate measurements.^The ratio of the rate of UF/sub 5/-dimer formation to the rate of monomer-fluorine recombination is insensitive to the cluster formation.^That ratio, k/sub mm//k/sub rm/ = 5.0 +/- 1.0, is the authors most reliable experimental result.^It, along with additional experimental data, give k/sub rm/ = 8.0 x 10/sup -12/ cm/sup 3/ molecule/sup -1/ s/sup -1/ and k/sub mm/ = 4.0 x 10/sup -11/ cm/sup 3/ molecule/sup -1/ s/sup -1/.^To obtain the dependence of reaction rates on s, the average UF/sub 5/ polymer size, the authors assumed that the rates were proportional to the collision rate.^The derived rate constants were k/sub pp/ = k/sub mm/s/sup 1/6/ cm/sup 3/ molecule/sup -1/ s/sup -1/ for cluster growth and k/sub rp/ = 4.1 x 10/sup -14/(1 + 2s/sup 1/3/)/sup 2/ cm/sup 3/ molecule/sup -1/ s/sup -1/ for reaction of fluorine atoms with polymeric UF/sub 5/.^The experimental procedure was to photolyze both F/sub 2/ and UF/sub 6/ in helium diluent with a KrF excimer laser to produce UF/sub 5/ and an excess of fluorine atoms.^This allowed the slower recombination reactions to compete with polymerization.^They monitored the transient concentration of UF/sub 6/ with an ultraviolet probe beam at 215 nm.^The recombination of fluorine atoms with UF/sub 5/ monomer is substantially faster than recombination with the polymer. |
Country of Publication | United States |
Language | English |
Format | Pages: 4821-4826 |
System Entry Date | 2001 May 13 |
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