Hydrogen abstraction reactions by atomic fluorine. IV. Temperature dependence of the intermolecular kinetic isotope effect for the nonthermal $sup 18$F+H$sub 2$ reaction

Journal Article · Thu Jan 01 04:00:00 EST 1976 · J. Chem. Phys., v. 64, no. 1, pp. 417-426

OSTI ID:4098445

Grant, E R; Root, J W

The nuclear recoil systems $sup 18$F vs H$sub 2$/C$sub 3$$F$$sub 6$ and $sup 18$F vs D$sub 2$/C$sub 3$$F$$sub 6$ were investigated from 273--347 degreeK over the full range of mixture compositions at a constant pressure of 1000 Torr. The results were systematized and interpreted within a nonthermal bimolecular rate constant framework. The phenomenological rate constants as well as their purely non-Boltzmann components exhibited significant composition and ambient temperature dependences. Most, if not all, of this latter effect was attributable to the $sup 18$F*+C$sub 3$$F$$sub 6$ reaction channel, either through an internal state coupling mechanism or through secondary decomposition of excited CF$sub 3$CFCF$sub 2$$sup 18$F radicals by $sup 18$F-atom loss. Preferred values for the thermal reaction fractions in extrapolated pure H$sub 2$ (or D$sub 2$) and C$sub 3$$F$$sub 6$ systems were 20+-10% and 20+-20%. The corresponding average intermolecular kinetic isotope effect for the pure non-Boltzmann $sup 18$F+H$sub 2$ reaction was 1.3+-0.1. (AIP)

• Research Organization: Department of Chemistry and Crocker Nuclear Laboratory, University of California, Davis, California 95616
• NSA Number: NSA-33-019696
• OSTI ID: 4098445
• Journal Information: J. Chem. Phys., v. 64, no. 1, pp. 417-426, Journal Name: J. Chem. Phys., v. 64, no. 1, pp. 417-426; ISSN JCPSA
• Country of Publication: United States
• Language: English

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