Understanding X-ray photoelectron spectra of ionic liquids: experiments and simulations of 1-butyl-3-methylimidazolium thiocyanate

Gousseva, E., Midgley, S. D., Seymour, J. M., Seidel, R. ORCID: https://orcid.org/0000-0003-2613-4106, Grau-Crespo, R. ORCID: https://orcid.org/0000-0001-8845-1719 and Lovelock, K. R. J. ORCID: https://orcid.org/0000-0003-1431-269X (2022) Understanding X-ray photoelectron spectra of ionic liquids: experiments and simulations of 1-butyl-3-methylimidazolium thiocyanate. Journal of Physical Chemistry B, 126 (49). pp. 10500-10509. ISSN 1520-6106 doi: 10.1021/acs.jpcb.2c06372

Abstract/Summary

We demonstrate a combined experimental and computational approach to probe the electronic structure and atomic environment of an ionic liquid, based on core level binding energies. The 1-butyl-3-methylimidazolium thiocyanate [C4C1Im][SCN] ionic liquid was studied using ab initio molecular dynamics, and results were compared against previously published and new experimental X-ray photoelectron spectroscopy (XPS) data. The long-held assumption that initial-state effects in XPS dominate the measured binding energies is proven correct, which validates the established premise that the ground state electronic structure of the ionic liquid can be inferred directly from XPS measurements. A regression model based upon site electrostatic potentials and intramolecular bond lengths is shown to account accurately for variations in core-level binding energies within the ionic liquid, demonstrating the important effect of long-range interactions on the core levels and throwing into question the validity of traditional single ion pair ionic liquid calculations for interpreting XPS data.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/109960
Item Type	Article
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Chemistry
Publisher	American Chemical Society
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