Superthermal Al Atoms as a Reactive-Atom Probe of Fluorinated Surfaces

Paul D. Lane, Thomas Gstir, Simon M. Purcell, Michal Swierczewski, Naomi S. Elstone, Duncan W. Bruce, John M. Slattery, Matthew L. Costen, Kenneth G. McKendrick

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
31 Downloads (Pure)


We demonstrate a proof-of-concept of a new analytical technique to measure relative F atom exposure at the surfaces of fluorinated materials. The method is based on reactive-atom scattering (RAS) of Al atoms, produced by pulsed laser ablation of solid Al at 532 nm. The properties of the incident ground-state Al were characterized by laser-induced fluorescence(LIF); at typical ablation fluences, the speed distribution is approximately Maxwellian at ∼45000 K, with a most-probable kinetic energy of 187 kJ mol–1 and a mean of 560 kJ mol–1 When these Al atoms impact the surfaces of perfluorinated solids (poly(tetrafluorethylene), PTFE) or liquids (perfluoropolyether, PFPE), gas-phase AlF products are clearly detectable by LIF on the AlF A–X band. Quantitative AlF yields were compared for a small representative set of a widely studied family of ionic liquids based on the common 1-alkyl-3-methylimidazolium ([Cnmim]+)cation. Yields of (1.9 ± 0.2):1 were found from [C2mim][Tf2N]and [C8mim][Tf2N], containing the common fluorinated bis(trifluoromethylsulfonyl)imide anion ([Tf2N]). This is in quantitative agreement with previous independent low-energy ion scattering (LEIS) measurements and consistent with other independent results indicating that the longer cationic alkyl chains cover a larger fraction of the liquid surface and hence reduce anion exposure. The expected null result was obtained for the ionic liquid [C2mim][EtSO4] which contains no fluorine. These results open the way for further characterization and the potential application of this new variant of the RAS-LIF method.

Original languageEnglish
Pages (from-to)5580-5590
Number of pages11
JournalJournal of Physical Chemistry A
Issue number26
Early online date23 Jun 2023
Publication statusPublished - 6 Jul 2023


  • Physical and Theoretical Chemistry

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry


Dive into the research topics of 'Superthermal Al Atoms as a Reactive-Atom Probe of Fluorinated Surfaces'. Together they form a unique fingerprint.

Cite this