Skip to main content

Research Repository

Advanced Search

Electron-impact-ionization dynamics of five C2 to C4 perfluorocarbons

Bull, J.N.; Bart, M.; Vallance, C.; Harland, P.W.

Electron-impact-ionization dynamics of five C2 to C4 perfluorocarbons Thumbnail


Authors

J.N. Bull

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 Mar 28, 2024
Journal Physical Review A
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

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.




You might also like



Downloadable Citations