Electron motion in the gases CF/sub 4/, C/sub 2/F/sub 6/, C/sub 3/F/sub 8/, and n-C/sub 4/F/sub 10/
The drift velocity w of electrons has been measured in the perfluoroalkanes n-C/sub N/F/sub 2//sub N//sub +2/ (N = 1--4) over the density-reduced electric field (E/N) range 0.03 x 10/sup -17/ V cm/sup 2/less than or equal toE/Nless than or equal to500 x 10/sup -17/ V cm/sup 2/ using a pulsed Townsend experimental method. The present measurements of w are the first to be obtained for C/sub 2/F/sub 6/, C/sub 3/F/sub 8/, and n-C/sub 4/F/sub 10/ at low E/N values. The electron-drift-velocity measurements in C/sub 3/F/sub 8/ and n-C/sub 4/F/sub 10/ are dependent on gas pressure at high E/N values, even after allowing for nonequilibrium and boundary corrections to the measured electron swarm transit time. This is the first observation of a pressure dependence in the electron drift velocity in these gases and is believed to be due to changes in the electron energy distribution function f(epsilon-c,E/N) with gas pressure resulting from increases in the density-normalized electron attachment coefficient eta/N with gas pressure. The perfluoroalkanes CF/sub 4/, C/sub 2/F/sub 6/, and C/sub 3/F/sub 8/ exhibit regions of pronounced negative differential conductivity (NDC) similar to but smaller in magnitude than that in CH/sub 4/. Possible mechanisms leading to the observation of NDC effects in these molecular gases are discussed.
- Research Organization:
- Atomic, Molecular and High Voltage Physics Group, Health and Safety Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
- OSTI ID:
- 7201166
- Journal Information:
- Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 38:1; ISSN PLRAA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360603* -- Materials-- Properties
ALKANES
ELECTRICAL EQUIPMENT
ELECTRON ATTACHMENT
ELECTRON DRIFT
ELECTRONEGATIVITY
EQUIPMENT
FLUIDS
FLUORINATED ALIPHATIC HYDROCARBONS
GASES
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROCARBONS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PLASMA SWITCHES
SWITCHES
VELOCITY