Kinetics following addition of sulfur fluorides to a weakly ionized plasma from 300 to 500 K: Rate constants and product determinations for ion-ion mutual neutralization and thermal electron attachment to SF{sub 5}, SF{sub 3}, and SF{sub 2}

Journal Article · Tue Dec 21 00:00:00 EST 2010 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.3520150· OSTI ID:21559964

Shuman, Nicholas S; Miller, Thomas M; Viggiano, A A ^[1]; Hazari, Nilay ^[2]; Luzik, Jr, Eddie D ^[2]

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1. Space Vehicles Directorate, Air Force Research Laboratory, Hanscom Air Force Base, Massachusetts 01731-3010 (United States)
2. Department of Chemistry, Yale University, New Haven, Connecticut 06520 (United States)

Rate constants for several processes including electron attachment to SF{sub 2}, SF{sub 3}, and SF{sub 5} and individual product channels of ion-ion mutual neutralization between SF{sub 6}{sup -}, SF{sub 5}{sup -}, and SF{sub 4}{sup -} with Ar{sup +} were determined by variable electron and neutral density attachment mass spectrometry. The experiments were conducted with a series of related neutral precursors (SF{sub 6}, SF{sub 4}, SF{sub 5}Cl, SF{sub 5}C{sub 6}H{sub 5}, and SF{sub 3}C{sub 6}F{sub 5}) over a temperature range of 300-500 K. Mutual neutralization rate constants for SF{sub 6}{sup -}, SF{sub 5}{sup -}, and SF{sub 4}{sup -} with Ar{sup +} are reported with uncertainties of 10-25% and show temperature dependencies in agreement with the theoretical value of T{sup -0.5}. Product branching in the mutual neutralizations is temperature independent and dependent on the electron binding energy of the anion. A larger fraction of product neutrals from the SF{sub 6}{sup -} mutual neutralization (0.9 {+-}0.1) are dissociated than in the SF{sub 5}{sup -} mutual neutralization (0.65 {+-} 0.2), with the SF{sub 4}{sup -} (0.7 {+-} 0.3) likely lying in between. Electron attachment to SF{sub 5} (k= 2.0 x 10{sup -8} {+-}{sub 1}{sup 2} cm{sup 3} s{sup -1} at 300 K) and SF{sub 3} (4 {+-} 3 x 10{sup -9} cm{sup 3} s{sup -1} at 300 K) show little temperature dependence. Rate constants of electron attachment to closed-shell SF{sub n} species decrease as the complexity of the neutral decreases.

• OSTI ID: 21559964
• Journal Information: Journal of Chemical Physics, Vol. 133, Issue 23; Other Information: DOI: 10.1063/1.3520150; (c) 2010 American Institute of Physics; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
74 ATOMIC AND MOLECULAR PHYSICS
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANIONS
ARGON IONS
BINDING ENERGY
CATIONS
DENSITY
ELECTRON ATTACHMENT
ELECTRON-MOLECULE COLLISIONS
ELECTRONS
MASS SPECTRA
MASS SPECTROSCOPY
PLASMA
REACTION KINETICS
SULFUR FLUORIDES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
CHARGED PARTICLES
COLLISIONS
ELECTRON COLLISIONS
ELEMENTARY PARTICLES
ENERGY
FERMIONS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
IONS
KINETICS
LEPTONS
MOLECULE COLLISIONS
PHYSICAL PROPERTIES
SPECTRA
SPECTROSCOPY
SULFUR COMPOUNDS