Electron Attachment and Detachment and the Electron Affinity of Cyclo-C4F8

Abstract

New measurements have been made of rate constants for electron attachment to c-C4F8 (octafluorocyclobutane) and thermal electron detachment from the parent anion, c-C4F8(-), over the temperature range 298-400 K in 133 Pa of He gas in a flowing-afterglow Langmuir-probe apparatus. From these data the electron affinity for c-C4F8 was determined, EA(c-C4F8) = 0.63 +/- 0.05 eV. The motivation was to resolve a discrepancy between our earlier EA estimate and a higher value (EA = 1.05 +/- 0.10 eV) reported from a recent experiment of Hiraoka et all. J. Chem. Phys. 116, 7574 (2002). The electron attachment rate constant is 9.3 +/- 3.0 x 10 (exp -9) cc/s at 298 K. The electron detachment rate constant is negligible at room temperature but climbs to 1945 +/- 680/s at 400 K. G3(MP2) calculations were carried out for the neutral (D sub 2d, Superscript A sub 1) and anion (D sub 4h, Superscript 2 A sub 2u) and yielded EAc-C4F8 (-). From these, dissociative electron attachment is found to be endothermic by at least 1.55 eV.

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Document Details

Document Type
Technical Report
Publication Date
Apr 15, 2004
Accession Number
ADA424035

Entities

People

  • Albert A Viggiano
  • Jeffrey F. Friedman
  • Thomas M Miller

Organizations

  • Air Force Research Laboratory

Tags

Communities of Interest

  • Biomedical
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Afterglows
  • Air Force
  • Air Force Research Laboratories
  • Attachment
  • Computational Science
  • Density Functional Theory
  • Electron Density
  • Electrons
  • Heat Capacity
  • Langmuir Probes
  • Mass Spectrometry
  • Measurement
  • Military Research
  • Probes
  • Puerto Rico
  • Quantum Numbers
  • Spacecraft

Readers

  • Analytical Mechanics
  • Molecular Photonics/Laser Physics

Technology Areas

  • Microelectronics