Electron Attachment and Detachment: C6F6
Abstract
Electron attachment to C(sub 6)F(sub 6) is especially interesting because of the large change in symmetry between the neutral (D(sub 6h)) and anion (C(sub 2v)). We have made measurements of rate constants for electron attachment to C(sub 6)F(sub 6) and thermal electron detachment from the parent anion, C(sub 6)F(sub 6), over the temperature range 297-400K. in 133 Pa of He gas. A flowing-afterglow Langmuir probe (FALP) apparatus was used for this work. At 298K, the electron attachment rate constant is kappa(sub a) = 8.6(plus or minus)3.0 x 10(exp 8) cu cm s(exp -1), and the detachment rate constant kappa (sub d) is approximately 35 s(exp-1). As the temperature increases kappa (sub d) increases rapidly, to about 3000 s(exp -1) at 400K. The attachment/detachment equilibrium implies that the electron affinity of C(sub 6)F(sub 6) is 0.53(plus or minus)0.05 eV. Density functional calculations were carried out in order to obtain thermal quantities needed to convert the equilibrium constant kappa(sub a)/kappa(sub d) into EA(C(sub 6)F(sub 6)). G3(MP2) calculations yielded an electron affinity of 0.454 eV. The fluoride affinity of C(sub 6)F(sub 6) was calculated to be 1.26 eV at 298 K using this same method. We expect the G3(MP2) results to be good within 0.1 eV.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2004
- Accession Number
- ADA423196
Entities
People
- Albert A Viggiano
- J. M. Vandoren
- T. M. Miller
Organizations
- Air Force Research Laboratory