Electron attachment to perfluorocarbon compounds. I. c-C/sub 4/F/sub 6/, 2-C/sub 4/F/sub 6/, 1,3-C/sub 4/F/sub 6/, c-C/sub 4/F/sub 8/ and 2-C/sub 4/F/sub 8/

Journal Article · Thu Feb 01 04:00:00 EST 1979 · J. Chem. Phys.; (United States)

OSTI ID:6387228

Christodoulides, A A; Christophorou, L G; Pai, R Y; Tung, C M

Electron attachment rates ..cap alpha..w, as a function of the pressure-reduced electric field E/P/sub 298/ and mean electron energy have been measured for trace amounts (<10/sup -3/ Torr) each of c-C/sub 4/F/sub 6/ (perfluorocyclobutene), 2-C/sub 4/F/sub 6/ (perfluoro-2-butyne), 1,3-C/sub 4/F/sub 6/ (perfluoro-1,3-butadiene), c-C/sub 4/F/sub 8/ (perfluorocyclobutane), and 2-C/sub 4/F/sub 8/ (perfluoro-2-butene) in mixtures with N/sub 2/ (pressures 500--2000 Torr) and Ar (pressures 500--1500 Torr) at T=298/sup 0/K. The thermal attachment rates for these molecules were found to be 4.89 x 10/sup 9/, 1.77 x 10/sup 9/, 4.26 x 10/sup 9/, 4.05 x 10/sup 8/, and 1.56 x 10/sup 9/ sec/sup -1/ Torr/sup -1/, respectively. From the ..cap alpha..w () data, the attachment cross sections sigma/sub a/(epsilon) as a function of electron energy epsilon have been determined using the swarm-unfolding technique and are reported. For all five perfluorocarbon molecules, sigma/sub a/(epsilon) are very large. They exhibit three distinct negative ion resonances with maxima at: approx.0.0, 0.19, and 0.80 eV for 2-C/sub 4/F/sub 6/; approx.0.0, 0.17, and 1.04 eV for 1,3-C/sub 4/F/sub 6/; approx.0.0, 0.22, and 0.48 eV for c-C/sub 4/F/sub 8/; and approx.0.0, 0.18, and 0.59 for 2-C/sub 4/F/sub 8/. For c-C/sub 4/F/sub 6/, only a shoulder with a possible maximum at approx.0.14 eV was observed, in addition to the maxima at approx.0.0 and 0.71 eV. Although the positions of the maxima in sigma/sub a/(epsilon) vary only slightly among these compounds, the magnitude of sigma/sub a/(epsilon) depends strongly on structure.

• Research Organization: Atomic, Molecular and High Voltage Physics Group, Health and Safety Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
• OSTI ID: 6387228
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 70:3; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular &amp; Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ANIONS
AROMATICS
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
DIELECTRIC MATERIALS
ELECTRICAL EQUIPMENT
ELECTRICAL INSULATORS
ELECTRON ATTACHMENT
ELECTRON COLLISIONS
ELECTRON-MOLECULE COLLISIONS
ENERGY DEPENDENCE
ENERGY RANGE
EQUIPMENT
EV RANGE
EV RANGE 01-10
FLUIDS
FLUORINATED AROMATIC HYDROCARBONS
GASES
HALOGENATED AROMATIC HYDROCARBONS
IONS
MOLECULAR IONS
MOLECULE COLLISIONS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS