Mechanism of thermal electron attachment to O/sub 2/: Isotope effect studies with /sup 18/O/sub 2/ in rare gases and some hydrocarbons

Journal Article · Wed Aug 01 04:00:00 EDT 1984 · J. Chem. Phys.; (United States)

OSTI ID:6661305

Shimamori, H; Hotta, H

Thermal electron attachment to /sup 18/O/sub 2/ has been studied at room temperature for mixtures with rare gases (He, Ne, Ar, Kr, and Xe) and hydrocarbons (CH/sub 4/, C/sub 2/H/sub 6/, C/sub 3/H/sub 8/, and neo-C/sub 5/H/sub 12/) as third bodies (M), and the results are compared with those for the corresponding /sup 16/O/sub 2/ systems. The obtained three-body attachment rate constants (k/sup 18//sub M/ ) for rare gases and CH/sub 4/ are nearly equal to, or even less than those for the /sup 16/O/sub 2/ systems (k/sup 16//sub M/ ), which strongly suggests that the attachment to van der Waals molecules (or the vdW-M mechanism) predominates in these systems. On the other hand, for C/sub 2/H/sub 6/, C/sub 3/H/sub 8/, and neo-C/sub 5/H/sub 12/ k/sup 18//sub M/ 's are about twice greater than k/sup 16//sub M/ 's, thus indicating the importance of the Bloch--Bradbury (or the B--B) mechanism. All the isotope-effect data imply that the well-known feature of the marked dependence of the three-body rate constants upon nature of third bodies originates mainly from the B--B mechanism, and also that the vdW-M mechanism becomes important only when the B--B rate constant is very small, as in the case of rare gases, N/sub 2/, and CH/sub 4/.

• Research Organization: Fukui Institute of Technology Gakuen 3-618, Fukui 910, Japan
• OSTI ID: 6661305
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 81:3; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ALKANES
ARGON
CHEMICAL REACTION KINETICS
COLLISIONS
DISPERSIONS
ELECTRON ATTACHMENT
ELECTRON COLLISIONS
ELECTRON-MOLECULE COLLISIONS
ELEMENTS
ETHANE
EVEN-EVEN NUCLEI
FLUIDS
GASES
HELIUM
HYDROCARBONS
ISOTOPE EFFECTS
ISOTOPES
KINETICS
KRYPTON
LIGHT NUCLEI
METHANE
MIXTURES
MOLECULE COLLISIONS
NEON
NONMETALS
NUCLEI
ORGANIC COMPOUNDS
OXYGEN
OXYGEN 18
OXYGEN ISOTOPES
PROPANE
RARE GASES
REACTION KINETICS
STABLE ISOTOPES
XENON