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Resolving X-Ray Photoelectron Spectra of Ionic Liquids with Difference Spectroscopy

Clarke, Coby James; Maxwell-Hogg, Steven; Smith, Emily F; Hawker, Rebecca R; Harper, Jason B; Licence, Peter

Resolving X-Ray Photoelectron Spectra of Ionic Liquids with Difference Spectroscopy Thumbnail


Coby James Clarke

Steven Maxwell-Hogg

Emily F Smith

Rebecca R Hawker

Jason B Harper


X-ray photoelectron spectroscopy (XPS) is a powerful element-specific technique to determine the composition and chemical state of all elements in an involatile sample. However, for elements such as carbon, the wide variety of chemical states produce complex spectra that are difficult to interpret, consequently concealing important information due to the uncertainty in signal identity. Here we report a process whereby chemical modification of carbon structures with electron withdrawing groups can reveal this information, providing accurate, highly refined fitting models far more complex than previously possible. This method is demonstrated with functionalised ionic liquids bearing chlorine or trifluoromethane groups that shift electron density from targeted locations. By comparing the C 1s spectra of non-functional ionic liquids to their functional analogues, a series of difference spectra can be produced to identify exact binding energies of carbon photoemissions, which can be used to improve the C 1s peak fitting of both samples. Importantly, ionic liquids possess ideal chemical and physical properties, which enhance this methodology to enable significant progress in XPS peak fitting and data interpretation.


Clarke, C. J., Maxwell-Hogg, S., Smith, E. F., Hawker, R. R., Harper, J. B., & Licence, P. (2019). Resolving X-Ray Photoelectron Spectra of Ionic Liquids with Difference Spectroscopy. Physical Chemistry Chemical Physics, 21(1), 114-123.

Journal Article Type Article
Acceptance Date Nov 28, 2018
Online Publication Date Nov 28, 2018
Publication Date Jan 7, 2019
Deposit Date Nov 29, 2018
Publicly Available Date Nov 29, 2019
Journal Physical Chemistry Chemical Physics
Print ISSN 1463-9076
Electronic ISSN 1463-9084
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Volume 21
Issue 1
Pages 114-123
Keywords Physical and Theoretical Chemistry; General Physics and Astronomy
Public URL
Publisher URL!divAbstract
Additional Information : This document is Similarity Check deposited; : Supplementary Information; : Single-blind; : Received 28 October 2018; Accepted 28 November 2018; Accepted Manuscript published 28 November 2018


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