Comparative study of electron and positron scattering from benzene (C{sub 6}H{sub 6}) and hexafluorobenzene (C{sub 6}F{sub 6}) molecules

Journal Article · Mon Sep 01 00:00:00 EDT 2003 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.68.032707· OSTI ID:20640181

Makochekanwa, C; Sueoka, O; Kimura, M ^[1]

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1. Graduate School of Science and Engineering, Yamaguchi University, Ube, Yamaguchi 755-8611, (Japan)

Total cross sections (TCSs) for electron and positron scattering from hexafluorobezene (C{sub 6}F{sub 6}) molecules have been measured by the linear transmission time-of-flight method and are presented. In addition, new systematic measurements have been also carried out for benzene (C{sub 6}H{sub 6})-molecule targets. The impact energies are 0.4-1000 eV and 0.2-1000 eV for electron and positron scattering, respectively. For the case of C{sub 6}F{sub 6}, two resonance peaks have been observed in C{sub 6}F{sub 6} electron TCSs: one at 0.8 eV attributed to the resonant capture of the incident electron into the {pi}{sup *} orbital, with the formation of a transient C{sub 6}F{sub 6}{sup -} anion, and the broad one in the range above 7 eV showing weak spikes at 14 and 30 eV, of which the 14-eV one has been attributed to another negative-ion resonance formation with decomposition either through the reemission of the electron or through dissociative electron attachment leading to F{sup -}, C{sub 5}F{sub 3}{sup -}, and C{sub 6}F{sub 5}{sup -} fragmented ions. In contrast, the positron TCSs show no conspicuous strong structure but 2 to 3 weak shoulders overlaid on a broad (6-100)-eV peak arising from a series of electronic excitations, positronium formations, and ionizations. A close comparison with those for C{sub 6}H{sub 6} sheds much light on better understanding of the underlying dynamics.

• OSTI ID: 20640181
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 3 Vol. 68; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ANIONS
BENZENE
CAPTURE
COMPARATIVE EVALUATIONS
DISSOCIATION
ELECTRON ATTACHMENT
ELECTRON-MOLECULE COLLISIONS
ELECTRONS
EV RANGE
EXCITATION
FLUORINE IONS
IONIZATION
MOLECULES
ORGANIC FLUORINE COMPOUNDS
POSITRON-MOLECULE COLLISIONS
POSITRONIUM
POSITRONS
RESONANCE
SCATTERING
TIME-OF-FLIGHT METHOD
TOTAL CROSS SECTIONS
VISIBLE RADIATION