Flowing afterglow measurements of the density dependence of gas-phase ion-ion mutual neutralization reactions

Journal Article · Tue May 28 00:00:00 EDT 2013 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4803159· OSTI ID:22118539

Shuman, Nicholas S.; Viggiano, Albert A. ^[1]; Johnsen, Rainer ^[2]

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1. Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117 (United States)
2. Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)

We have studied the dependence of several ion-ion mutual neutralization (MN) reactions on helium density in the range from 1.6 Multiplication-Sign 10{sup 16} to 1.5 Multiplication-Sign 10{sup 17} cm{sup -3} at 300 K, using the Variable Electron and Neutral Density Attachment Mass Spectrometry method. The rate coefficients of the reactions Ar{sup +}+ Br{sub 2}{sup -}, Ar{sup +}+ SF{sub 6}{sup -}, and Ar{sup +}+ C{sub 7}F{sub 14}{sup -} were found to be independent of gas density over the range studied, in disagreement with earlier observations that similar MN reactions are strongly enhanced at the same gas densities. The cause of the previous enhancement with density is traced to the use of 'orbital-motion-limit' theory to infer ion densities from the currents collected by ion-attracting Langmuir probes in a region where it is not applicable.

• OSTI ID: 22118539
• Journal Information: Journal of Chemical Physics, Vol. 138, Issue 20; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
AFTERGLOW
ANIONS
ARGON
ARGON IONS
ATOM-MOLECULE COLLISIONS
BROMINE
CATIONS
HELIUM
ION DENSITY
ION-MOLECULE COLLISIONS
LANGMUIR PROBE
MASS SPECTROSCOPY
ORGANIC COMPOUNDS
PLASMA DENSITY
REACTION KINETICS
SULFUR FLUORIDES
TEMPERATURE RANGE 0273-0400 K