Low-energy electron interactions with organic molecules: Negative ion states of fluorobenzenes

Journal Article · Sun Oct 15 04:00:00 EDT 1978 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.437045· OSTI ID:6687281

Frazier, J R; Christophorou, L G; Carter, J G; Schweinler, H C

An electron transmission technique has been employed to determine the positions of the three ..pi..-negative ion states (configurations ..pi../sub 1//sup 2/..pi../sup 2//sub 2/..pi../sup 2//sub 3/..pi../sub 4//sup 1/, ..pi../sup 2//sub 1/..pi../sup 2//sub 2/..pi../sup 2//sub 3/..pi../sup 1//sub 5/, and ..pi../sup 2//sub 1/..pi../sub 2//sup 2/..pi../sup 2//sub 3/..pi../sup 1//sub 6/) of benzene and fluorobenzenes in the vapor phase. These are 1.13 (1.35), 1.13 (1.35), (4.80) eV for benzene; 0.82 (0.91), (1.40), (4.66) eV for fluorobenzene; 0.53 (0.62), (1.41), (4.51) eV for p-difluorobenzene; (0.77), (0.77), (4.48) eV for 1,3,5-trifluorobenzene; 0.34, (0.50), (1.29), (4.51) eV for 2,3,5,6-tetrafluorobenzene; <0.15 (0.36), (1.19), (4.53) eV for pentafluorobenzene; and (0.42), (0.42), (4.50) eV for hexafluorobenzene. The numbers in parentheses are the vertical attachment energies, and those not in parentheses are the 0..-->..0 transitions. On the basis of these data, the first ..pi..-electron affinities (E.A.) of the isolated molecules of these compounds are equal to -1.13, -0.82, -0.53, >-0.77, -0.34, > or =-0.15, >-0.42 eV for benzene, fluorobenzene, difluorobenzene, 1,3,5-trifluorobenzene, 2,3,5,6-tetrafluorobenzene, pentafluorobenzene, and hexafluorobenzene, respectively. The present results, therefore, suggest that the ..pi..-electron affinity of C/sub 6/F/sub 6/ is <0.0 eV, although C/sub 6/F/sub 6/ is known to have a positive (+1.8 eV) E.A. and although the parent ion, C/sub 6/F/sub 6//sup -/*, is known to form with a very large electron attachment cross section at approx.0.0 eV and to be long lived (approx.12 ..mu..sec). These findings are reconciled, discussed in connection with previously published data, and are theoretically treated. They extend our understanding of the negative ion states of substituted benzenes.

• Research Organization: Health and Safety Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
• OSTI ID: 6687281
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 69:8; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular &amp; Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
AFFINITY
AROMATICS
BENZENE
COLLISIONS
ELECTRON ATTACHMENT
ELECTRON COLLISIONS
ELECTRON-MOLECULE COLLISIONS
ELECTRONEGATIVITY
FLUORINATED AROMATIC HYDROCARBONS
HALOGENATED AROMATIC HYDROCARBONS
HYDROCARBONS
IONIZATION POTENTIAL
MOLECULE COLLISIONS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS