J.N. Bull
Electron-impact-ionization dynamics of five C2 to C4 perfluorocarbons
Bull, J.N.; Bart, M.; Vallance, C.; Harland, P.W.
Authors
M. Bart
C. Vallance
P.W. Harland
Abstract
Perfluorocarbons (PFCs) are man-made compounds whose ion physics exhibit complex interplays between statistical and nonstatistical fragmentation and intramolecular rearrangement processes. One probe of such processes is the energy-dependent electron-impact-ionization cross section. Partial electron-impact-ionization cross sections are reported for the fragments arising from five C2 to C4 PFCs, namely, C2F6, C3F8, C3F6, CF2=CF-CF=CF2, and CF3-C≡C-CF3, over the energy range from threshold to ∼210 eV. Care was taken to maximize ion collection efficiency and to minimize discrimination against ions produced with high kinetic-energy release, and the measured cross sections have been calibrated using independent absolute total (gross) ionization efficiency curves measured previously in the same laboratory with an instrument that was designed to essentially have unit detection efficiency. Total ionization cross sections have also been modeled using the binary-encounter Bethe model, and the shortcomings of the model when applied to perfluorinated compounds are discussed. Analysis of the mass spectral fragmentation patterns in combination with ab initio energetics suggests that nonstatistical dissociative ionization processes play a significant role in the fragmentation dynamics of saturated PFCs. In contrast, unsaturated PFCs exhibit long-lived parent ions, which tend to undergo a higher degree of statistical dissociation following ionization, involving considerable intramolecular rearrangement.
Citation
Bull, J., Bart, M., Vallance, C., & Harland, P. (2013). Electron-impact-ionization dynamics of five C2 to C4 perfluorocarbons. Physical Review A, 88(6), Article 062710. https://doi.org/10.1103/physreva.88.062710
| Journal Article Type | Article |
|---|---|
| Publication Date | Dec 1, 2013 |
| Deposit Date | Mar 12, 2014 |
| Publicly Available Date | Aug 5, 2014 |
| Journal | Physical Review A - Atomic, Molecular, and Optical Physics |
| Print ISSN | 1050-2947 |
| Electronic ISSN | 1094-1622 |
| Publisher | American Physical Society |
| Peer Reviewed | Peer Reviewed |
| Volume | 88 |
| Issue | 6 |
| Article Number | 062710 |
| DOI | https://doi.org/10.1103/physreva.88.062710 |
| Public URL | https://durham-repository.worktribe.com/output/1468048 |
Files
Published Journal Article
(506 Kb)
PDF
Copyright Statement
Reprinted with permission from the American Physical Society: Phys. Rev. A 88, 062710 © (2013) by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modified, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.