Mechanism of thermal electron attachment in N/sub 2/O and N/sub 2/O-hydrocarbon mixtures in the gas phase

Journal Article · Wed Mar 15 04:00:00 EST 1978 · J. Chem. Phys.; (United States)

OSTI ID:5119868

Shimamori, H; Fessenden, R W

The attachment of thermal electrons to nitrous oxide at room temperature has been studied, following pulse radiolysis, by a microwave conductivity technique. For pure N/sub 2/O at pressures from 10 to 300 torr, the results are explained by a combination of two-body attachment followed by reactions leading to partial electron detachment, a two step three-body process, and a process giving overall four-body behavior. The results for mixtures of N/sub 2/O with alkanes (C/sub 2/H/sub 6/, C/sub 3/H/sub 8/, n-C/sub 4/H/sub 10/, iso-C/sub 4/H/sub 10/, n-C/sub 5/H/sub 12/, and neo-C/sub 5/H/sub 12/) and butenes (1-, 2-cis-, 2-trans-, and iso) are also explained in the same way, but with no electron detachment. Common values of 5 x 10/sup -15/ cm/sup 3//molecule sec for the two-body rate constant and 4.6 x 10/sup -33/ cm/sup 6//molecule/sup 2/ sec for the three-body rate constant (with N/sub 2/O as the third body) explain the data. The three-body rate constants increase with molecular complexity (6 x 10/sup -34/ cm/sup 6//molecule/sup 2/ sec for C/sub 2/H/sub 6/ to 1.55 x 10/sup -31/ cm/sup 6//molecule/sup 2/ sec for neo-C/sub 5/H/sub 12/). The four-body rate constants range from approx.10/sup -53/ to approx.10/sup -51/cm/sup 9//molecule/sup 3/ sec. The branched compounds such as neopentane and isobutene have higher three-body rate constants than the linear isomers. The attachment rates of mixtures of those compounds with the higher three-body rate constants appear to saturate as pressures increase. From the results for N/sub 2/O-neo-C/sub 5/H/sub 12/ mixtures a value of (5.8 +- 0.6) x 10/sup -13/ cm/sup 3//molecule sec has been determined for the rate constant of the initial two-body electron capture by N/sub 2/O to form a short-lived N/sub 2/O/sup -/. The autoionization lifetime of N/sub 2/O/sup -/ is estimated to be 1.8 x 10/sup -10/ sec or greater. The problem of excess nitrogen in N/sub 2/O-hydrocarbon radiolysis is discussed in relation to these results.

• Research Organization: Radiation Laboratory)/sup a/ and Department of Chemistry, University of Notre Dame, Notre Dame, Indiana 46556
• OSTI ID: 5119868
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 68:6; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
ALKANES
ALKENES
BUTENES
CHALCOGENIDES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
DISPERSIONS
ELECTRON ATTACHMENT
HYDROCARBONS
IRRADIATION
KINETICS
MIXTURES
NITROGEN COMPOUNDS
NITROGEN OXIDES
NITROUS OXIDE
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PULSED IRRADIATION
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIOLYSIS
REACTION KINETICS