Theoretical reconstruction and elementwise analysis of photoelectron spectra for imidazolium-based ionic liquids

Markus Reinmöller; Angela Ulbrich; Tomonori Ikari; Julia Preiss; Oliver Höfft; Frank Endres; Stefan Krischok; Wichard J D Beenken

doi:10.1039/c1cp22152c

Theoretical reconstruction and elementwise analysis of photoelectron spectra for imidazolium-based ionic liquids

Phys Chem Chem Phys. 2011 Nov 21;13(43):19526-33. doi: 10.1039/c1cp22152c. Epub 2011 Oct 4.

Authors

Markus Reinmöller¹, Angela Ulbrich, Tomonori Ikari, Julia Preiss, Oliver Höfft, Frank Endres, Stefan Krischok, Wichard J D Beenken

Affiliation

¹ Institute of Physics and Institute of Micro- and Nanotechnologies, Ilmenau University of Technology, P.O. Box 100 565, 98684 Ilmenau, Germany.

PMID: 21971301
DOI: 10.1039/c1cp22152c

Abstract

We have recently measured core level and valence band XPS, UPS, and MIES spectra of two room temperature ionic liquids composed of bis(trifluoromethylsulfonyl)imide anions ([Tf(2)N](-)) and either 1-ethyl-3-methyl-imidazolium ([EMIm](+)) or 1-octyl-3-methyl-imidazolium cations ([OMIm](+)). [T. Ikari, A. Keppler, M. Reinmöller, W. J. D. Beenken, S. Krischok, M. Marschewski, W. Maus-Friedrichs, O. Höfft and F. Endres, e-J. Surf. Sci. Nanotechnol., 2010, 8, 241.] In the present work we analyze these spectra by means of partial density of states (pDOS) as calculated from a single ion pair of the respective ionic liquid using density functional theory (DFT). Subsequently we reconstruct the XPS and UPS spectra by considering photoemission cross sections and analyze the MIES spectra by pDOS, which provides us decisive hints to the ionic liquid surface structure.