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

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.