Thermal electron attachment to F2

Authors

• Nicholas S. Shuman, Air Force Research Laboratory
• Thomas M. Miller, Air Force Research Factory
• Albert A. Viggiano, Air Force Research FactoryFollow
• Ilya I. Fabrikant, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

2013

Citation

PHYSICAL REVIEW A 88, 062708 (2013)

Comments

© 2013 American Physical Society

DOI: 10.1103/PhysRevA.88.062708

Abstract

Rate constants have been measured from 300 to 700 K for thermal electron attachment to F₂ using two flowing afterglow–Langmuir probe apparatuses. Dissociative attachment yielding F⁻ is observed with a rate constant of 5.0 ± 1.3 × 10⁻⁹ cm³ s⁻¹ at 300 K, rising to 9.6 ± 2.4 × 10⁻⁹ cm³ s⁻¹ at 700 K, well below the previously accepted values of McCorkle et al. [D. L.McCorkle, L. G. Christophorou, A. A. Christodoulides, and L. Pichiarella, J. Chem. Phys. 85, 1966 (1986)]. The absolute concentration of F₂ reaching the afterglowis verified by measuring the near-collisional rate constant (4.5 ± 1.5 × 10⁻¹⁰ cm³ s⁻¹) for Ar+ + F₂→ArF⁺ + F. Prior attempts to apply R-matrix calculations to the F₂ + e⁻ system have failed to explain previously reported thermal and nonthermal attachment rate constants along with high-resolution, low-energy attachment cross sections. The present results are reproduced exceptionally well by R-matrix calculations employing previously calculated resonance widths without adjustment.