Electron affinities and activation energies for reactions with thermal electrons: SF{sub 6} and SF{sub 5}

Journal Article · Sat Sep 15 04:00:00 EDT 2007 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.76.032508· OSTI ID:21015968

Chen, E C. M. ^[1]; Chen, E S ^[2]

---

1. University of Houston-Clear Lake, Houston, Texas 77058 (United States)
2. Wentworth Foundation, 4039 Drummond, Houston, Texas 77025 (United States)

Negative ion mass spectrometry and pulsed discharge electron capture detector data for thermal electron attachment to SF{sub 6} are reported. Electron affinities and activation energies for SF{sub 6} and SF{sub 5} are obtained from these data and literature magnetron, swarm, beam, and collisional ionization data. The thermodynamic and kinetic data cover temperatures from 50 to 7500 K. The largest electron affinity of SF{sub 6}, 2.60(10) eV is assigned to the adiabatic electron affinity. The numbers in parentheses indicate uncertainties. Excited state values are (in eV) 2.45(3), 2.20(3), 2.00(3), 1.80(3), 1.60(3), 1.20(3), 1.04(3), 0.80(3), 0.65(3), 0.45(3), 0.35(3), 0.25(3), and 0.10(10). The activation energies range from near zero to 0.65(2) eV. The adiabatic electron affinity of SF{sub 5}, 3.85(2) eV and an excited state value, 2.77(5) eV are obtained from a kinetic analysis of published magnetron data. The energies for dissociative electron attachment to give SF{sub 5}(-), F(-), and excited state SF{sub 5}(-) are 0.20(11) eV, 0.65(10) eV, and 1.28(11) eV from the SF{sub 5}-F dissociation energy, the electron affinity of the fluorine atom, and these values. The average relative anion bond orders for the bonding curves is 0.63(2) and for the antibonding curves is 0.30(2). Fourteen Herschbach ionic Morse Person empirical curves are calculated from these data. Six bonding and six antibonding curves are pseudo-two-dimensional cuts through the multidimensional surface. Representative long-range anionic curves are calculated in reaction coordinates analogous to Marcus parabolas.

• OSTI ID: 21015968
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 3 Vol. 76; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ACTIVATION ENERGY
ANIONS
BEAMS
BONDING
DISSOCIATION ENERGY
ELECTRON ATTACHMENT
ELECTRON-CAPTURE DETECTORS
ELECTRON-MOLECULE COLLISIONS
ELECTRONS
EV RANGE
EXCITED STATES
IONIZATION
IONIZATION POTENTIAL
MAGNETRONS
MASS SPECTROSCOPY
SIMULATION
SULFUR FLUORIDES
TWO-DIMENSIONAL CALCULATIONS